presentation in labour

Fetal Presentation, Position, and Lie (Including Breech Presentation)

Variations in Fetal Position and Presentation |

During pregnancy, the fetus can be positioned in many different ways inside the mother's uterus. The fetus may be head up or down or facing the mother's back or front. At first, the fetus can move around easily or shift position as the mother moves. Toward the end of the pregnancy the fetus is larger, has less room to move, and stays in one position. How the fetus is positioned has an important effect on delivery and, for certain positions, a cesarean delivery is necessary. There are medical terms that describe precisely how the fetus is positioned, and identifying the fetal position helps doctors to anticipate potential difficulties during labor and delivery.

Presentation refers to the part of the fetus’s body that leads the way out through the birth canal (called the presenting part). Usually, the head leads the way, but sometimes the buttocks (breech presentation), shoulder, or face leads the way.

Position refers to whether the fetus is facing backward (occiput anterior) or forward (occiput posterior). The occiput is a bone at the back of the baby's head. Therefore, facing backward is called occiput anterior (facing the mother’s back and facing down when the mother lies on her back). Facing forward is called occiput posterior (facing toward the mother's pubic bone and facing up when the mother lies on her back).

Lie refers to the angle of the fetus in relation to the mother and the uterus. Up-and-down (with the baby's spine parallel to mother's spine, called longitudinal) is normal, but sometimes the lie is sideways (transverse) or at an angle (oblique).

For these aspects of fetal positioning, the combination that is the most common, safest, and easiest for the mother to deliver is the following:

Head first (called vertex or cephalic presentation)

Facing backward (occiput anterior position)

Spine parallel to mother's spine (longitudinal lie)

Neck bent forward with chin tucked

Arms folded across the chest

If the fetus is in a different position, lie, or presentation, labor may be more difficult, and a normal vaginal delivery may not be possible.

Variations in fetal presentation, position, or lie may occur when

The fetus is too large for the mother's pelvis (fetopelvic disproportion).

The uterus is abnormally shaped or contains growths such as fibroids .

The fetus has a birth defect .

There is more than one fetus (multiple gestation).

Position and Presentation of the Fetus

Toward the end of pregnancy, the fetus moves into position for delivery. Normally, the presentation is vertex (head first), and the position is occiput anterior (facing toward the pregnant person's spine) and with the face and body angled to one side and the neck flexed.

Variations in fetal presentations include face, brow, breech, and shoulder. Occiput posterior position (facing forward, toward the mother's pubic bone) is less common than occiput anterior position (facing backward, toward the mother's spine).

Variations in Fetal Position and Presentation

Some variations in position and presentation that make delivery difficult occur frequently.

Occiput posterior position

In occiput posterior position (sometimes called sunny-side up), the fetus is head first (vertex presentation) but is facing forward (toward the mother's pubic bone—that is, facing up when the mother lies on her back). This is a very common position that is not abnormal, but it makes delivery more difficult than when the fetus is in the occiput anterior position (facing toward the mother's spine—that is facing down when the mother lies on her back).

When a fetus faces up, the neck is often straightened rather than bent,which requires more room for the head to pass through the birth canal. Delivery assisted by a vacuum device or forceps or cesarean delivery may be necessary.

Breech presentation

In breech presentation, the baby's buttocks or sometimes the feet are positioned to deliver first (before the head).

When delivered vaginally, babies that present buttocks first are more at risk of injury or even death than those that present head first.

The reason for the risks to babies in breech presentation is that the baby's hips and buttocks are not as wide as the head. Therefore, when the hips and buttocks pass through the cervix first, the passageway may not be wide enough for the head to pass through. In addition, when the head follows the buttocks, the neck may be bent slightly backwards. The neck being bent backward increases the width required for delivery as compared to when the head is angled forward with the chin tucked, which is the position that is easiest for delivery. Thus, the baby’s body may be delivered and then the head may get caught and not be able to pass through the birth canal. When the baby’s head is caught, this puts pressure on the umbilical cord in the birth canal, so that very little oxygen can reach the baby. Brain damage due to lack of oxygen is more common among breech babies than among those presenting head first.

In a first delivery, these problems may occur more frequently because a woman’s tissues have not been stretched by previous deliveries. Because of risk of injury or even death to the baby, cesarean delivery is preferred when the fetus is in breech presentation, unless the doctor is very experienced with and skilled at delivering breech babies or there is not an adequate facility or equipment to safely perform a cesarean delivery.

Breech presentation is more likely to occur in the following circumstances:

Labor starts too soon (preterm labor).

The uterus is abnormally shaped or contains abnormal growths such as fibroids .

Abnormal Fetal lie, Malpresentation and Malposition

Original Author(s): Anna Mcclune Last updated: 1st December 2018 Revisions: 12

1 Definitions
2 Risk Factors
3.2 Presentation
3.3 Position
4 Investigations
5.1 Abnormal Fetal Lie
5.2 Malpresentation
5.3 Malposition

The lie, presentation and position of a fetus are important during labour and delivery.

In this article, we will look at the risk factors, examination and management of abnormal fetal lie, malpresentation and malposition.

Definitions

Longitudinal, transverse or oblique
Cephalic vertex presentation is the most common and is considered the safest
Other presentations include breech, shoulder, face and brow
Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) – this is ideal for birth
Other positions include occipito-posterior and occipito-transverse.

Note: Breech presentation is the most common malpresentation, and is covered in detail here .

Fig 1 – The two most common fetal presentations: cephalic and breech.

Risk Factors

The risk factors for abnormal fetal lie, malpresentation and malposition include:

Multiple pregnancy
Uterine abnormalities (e.g fibroids, partial septate uterus)
Fetal abnormalities
Placenta praevia
Primiparity

Identifying Fetal Lie, Presentation and Position

The fetal lie and presentation can usually be identified via abdominal examination. The fetal position is ascertained by vaginal examination.

For more information on the obstetric examination, see here .

Face the patient’s head
Place your hands on either side of the uterus and gently apply pressure; one side will feel fuller and firmer – this is the back, and fetal limbs may feel ‘knobbly’ on the opposite side

Presentation

Palpate the lower uterus (above the symphysis pubis) with the fingers of both hands; the head feels hard and round (cephalic) and the bottom feels soft and triangular (breech)
You may be able to gently push the fetal head from side to side

The fetal lie and presentation may not be possible to identify if the mother has a high BMI, if she has not emptied her bladder, if the fetus is small or if there is polyhydramnios .

During labour, vaginal examination is used to assess the position of the fetal head (in a cephalic vertex presentation). The landmarks of the fetal head, including the anterior and posterior fontanelles, indicate the position.

Fig 2 – Assessing fetal lie and presentation.

Investigations

Any suspected abnormal fetal lie or malpresentation should be confirmed by an ultrasound scan . This could also demonstrate predisposing uterine or fetal abnormalities.

Abnormal Fetal Lie

If the fetal lie is abnormal, an external cephalic version (ECV) can be attempted – ideally between 36 and 38 weeks gestation.

ECV is the manipulation of the fetus to a cephalic presentation through the maternal abdomen.

It has an approximate success rate of 50% in primiparous women and 60% in multiparous women. Only 8% of breech presentations will spontaneously revert to cephalic in primiparous women over 36 weeks gestation.

Complications of ECV are rare but include fetal distress , premature rupture of membranes, antepartum haemorrhage (APH) and placental abruption. The risk of an emergency caesarean section (C-section) within 24 hours is around 1 in 200.

ECV is contraindicated in women with a recent APH, ruptured membranes, uterine abnormalities or a previous C-section .

Fig 3 – External cephalic version.

Malpresentation

The management of malpresentation is dependent on the presentation.

Breech – attempt ECV before labour, vaginal breech delivery or C-section
Brow – a C-section is necessary
If the chin is anterior (mento-anterior) a normal labour is possible; however, it is likely to be prolonged and there is an increased risk of a C-section being required
If the chin is posterior (mento-posterior) then a C-section is necessary
Shoulder – a C-section is necessary

Malposition

90% of malpositions spontaneously rotate to occipito-anterior as labour progresses. If the fetal head does not rotate, rotation and operative vaginal delivery can be attempted. Alternatively a C-section can be performed.

Usually the fetal head engages in the occipito-anterior position (the fetal occiput facing anteriorly) - this is ideal for birth

If the fetal lie is abnormal, an external cephalic version (ECV) can be attempted - ideally between 36 and 38 weeks gestation.

Breech - attempt ECV before labour, vaginal breech delivery or C-section

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Introduction
Mechanism of Normal Labor
Practice Recommendations
Study Assessment – Optional
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This chapter should be cited as follows: Dutta A, Glob. libr. women's med ., ISSN: 1756-2228; DOI 10.3843/GLOWM.414323

The Continuous Textbook of Women’s Medicine Series – Obstetrics Module

Labor and delivery

Volume Editor: Dr Edwin Chandraharan , Director Global Academy of Medical Education and Training, London, UK

Presentation and Mechanism of Labor

First published: February 2021

Study Assessment Option

By completing 4 multiple-choice questions (randomly selected) after studying this chapter readers can qualify for Continuing Professional Development awards from FIGO plus a Study Completion Certificate from GLOWM See end of chapter for details

INTRODUCTION

The mechanism of normal labor is series of events that take place in the genital organ that allow the birth of a viable fetus at term; followed by expulsion of placenta and membrane from the vagina.

World Health Organization defines normal labor as starting spontaneously at term (37 completed weeks of gestation) for a fetus with cephalic presentation, progressing without maternal or fetal complication, and resulting in the delivery of fetus followed by placenta and membranes.

The factors that trigger labor at term are not clearly understood; it is postulated that it is a result of changes in the hypothalamic–pituitary–adrenal axis, increasing fetal cortisol, and placental enzymatic functions. Complex interactions of hormones between uterus, placenta and fetus. Fetal dehyroepiandrosterone sulfate (DHEAS) is converted to estriol and estradiol by the placenta. 1 This potentiates oxytocin receptors in the myometrium, reduces the progesterone/estrogen ratio and upregulates myometrial gap junctions to facilitate uterine contractions. The onset of labor is also associated with an increase in prostaglandin production in the placental and cervix, furthering inducing their receptors and facilitating cervical ripening (PGE 2 ) and uterine contractions (PGF 2a ). 2 , 3 , 4

MECHANISM OF NORMAL LABOR

For a successful normal labor a coordinated interaction of the uterine activity (power), maternal pelvis (passage) and fetus (passenger) is required.

Maternal pelvis (passage)

Bony pelvis: ilium, ischium, pubis, sacrum and coccyx.

The maternal pelvis is made of five bones (Figure 1): the sacrum and coccyx posteriorly, two innominate bones on each side, and the pubic bone anteriorly. The bones are articulated together by four joints: anteriorly symphysis pubis, two sacroiliac joints posteriorly and the sacrococcygeal joint inferiorly.

The pelvic brim extends from the sacral promontory, along the ilium on each side circularly along the ridge divides the pelvis into upper false pelvis and lower true pelvis.

The significance of the false pelvis is to support the pregnant uterus; the true pelvis is a bony passage for fetus to pass during labor.

The true pelvis is shallow anteriorly, formed by the symphysis pubis (4–5 cm), and deep posteriorly, formed by the sacrum and coccyx (10 cm). It is divided into three parts – inlet, cavity and outlet (Figure 1).

The pelvic inlet has a wide transverse diameter – approximately 13 cm, the midcavity of the pelvis is round, whilst the outlet has a wide anterior posterior diameter.

Uterine activity (power)

The uterine contraction is characterized by its intensity, frequency, and duration. External tocodynamometry is a qualitative measurement of uterine activity, records uterine activity and correlates fetal heart rate (FHR) pattern with uterine contraction.

Quantitative assessment of intrauterine pressure to measure the strength of uterine contraction is done by placement of an intrauterine catheter. This is measured in Montevideo units (MVU). Uterine activity varies in different stages of labor: latent phase approximately 100 MVUs, active phase of labor 175 MVUs and 250 MVUs during the second stage. 5 , 6

Fetus (passenger)

For a successful outcome, the fetal skull, shoulders, trunk and buttocks should pass through maternal pelvis.

Several variables in the fetus influence its journey through the birth canal.

Fetal size can be estimated by palpation, ultrasound scan and customized growth chart but all of these methods are subjected to large degree of error.

Fetal lie is the relationship of the long axis of the fetus relative to longitudinal axis of the uterus. A fetus in longitudinal lie is suitable for vaginal delivery.

Presentation – the part of the fetus that directly overlies the lower pole of the uterus/pelvic inlet. Hence in longitudinal lie the fetus may be cephalic or breech and in oblique/transverse shoulders or compound with more than one part overlying the pelvic inlet.

Attitude – position of fetal head with the fetal spine (the degree of flexion and/or extension of the fetal head. Flexion of fetal head is a favored attitude as it presents the smallest diameter to the maternal pelvis (Figures 2–5).

Flexion-suboccipitobrematic 9.5 cm.

Deflexed suboccipitofrontal 10 cm.

Deflexed occipitofrontal 11 cm.

Extended mentovertical 13 cm.

Position is the relationship of the presenting part to the maternal pelvis.

Stages of labor : labor is describes in three stages:

First stage – on set of regular uterine contractions, progressive effacement and dilatation of the cervix to 10 cm. This stage is divided into latent and active phase. The duration of the latent phase may vary from days to weeks in primiparous women. It is characterized by regular painful uterine contraction, progressive effacement/dilation of the cervix. Active phase is when the cervical dilatation is 4 cm and beyond, in presence of regular painful uterine contraction. For a nullipara the first stage of labor this lasts on average 8–18 hours; in multiparous women it is between 5 and 12 hours.
Second stage – t he stage in labor from full dilatation of the cervix to delivery of the baby is defined as second stage. Initial second stage is termed as passive second stage: when there is no voluntary maternal effort. Active second stage is when there is active maternal effort/expulsive uterine contraction to progressively move the presenting part to deliver the baby. Birth is expected within 3 hours of the start of active second stage in most nulliparous and within 2 hours in most multiparous women. 7
Third stage – t his is the time from the birth of baby till expulsion of placenta and membranes. This is usually completed with 30 minutes of birth following active management or 60 minutes if physiological.

Mechanism of normal labor

The fetus undertakes a series of movements to adapt the smallest possible diameter of the presenting part to the anatomy of the maternal pelvis. The commonest situation is fetus in longitudinal lie, cephalic position and well-flexed attitude.

For description, head is only the index, the trunk also participates in and probably also initiates some movements. These movements are:

Engagement;
Internal rotation;
Restitution;
External rotation.
Engagement is the mechanism by which the greatest transverse diameter of the fetal head: the biparietal diameter (BPD) (9.4 cm) is at or has passed the pelvic inlet (brim). In nulliparous women engagement occurs weeks prior to onset of labor, whereas in multiparous women it may occur in labor.
Descent is a continuous process throughout the first and second stage of labor.
Flexion – t he head is already flexed to an extent at the time of engagement and further flexion occurs during the first stage of labor due to soft tissue resistance of the pelvis.
The flexion facilitates the shortest anterior – posterior diameter suboccipito – bregmatic (9.5 cm) to be presented at the pelvic outlet.
Internal rotation is defined as turning of the head in such a manner that the occiput gradually moves anteriorly towards the symphysis pubis. This carries the long diameter of the head into the antero – posterior diameter (A-P), i.e. the longest diameter of the pelvic outlet from the previous occipito lateral positions.
Internal rotation brings the occiput forwards under the pubic arch. The fetal shoulder enters the pelvis in the transverse diameter. This results in degree of rotation at the fetal neck.
Extension (Figure 6) – t he force of uterine contraction and active maternal effort along with the pelvic floor muscles facilitates the birth of head by extension. The chin slides over the edge of the perineum and becomes separated from the chest wall, i.e. the head becomes extended. The vaginal outlet is stretched and crowning occurs. With progressive distension of the perineum the occiput, forehead, mouth and chin are delivered successively.
Restitution (Figure 7) – t he visible external movement of the fetal head that corrects the torsion of neck sustained during internal rotation. The direction of movement is opposite to that of the internal rotation (45°).
This allows the head to come back in line with the shoulders. The occiput points to the maternal thigh of the corresponding side to which it originally lies.
External rotation (Figure 8) – t he movement of the head due to the internal rotation of the shoulder as it comes in the antero – posterior diameter of the pelvic outlet. This is visible externally in a direction opposite to internal rotation. It occurs in the same direction as restitution. Now the shoulders are in antero – posterior diameter (A-P) axis. The anterior shoulder escapes under the pubic arch, while the posterior shoulder sweeps over the perineum.
After the delivery of the shoulders, the rest of body is delivered spontaneously by lateral flexion.

Fetal head position at birth by extension.

Fetal head restitution.

Fetal head external rotation.

Labor is a crucial time for the mother, family member and the fetus. This is the most perilous journey under taken by the fetus in utero. For the clinician it is equally important to know and identify any deviation from the normal pathway.

Despite immense development in imaging techniques to assist in making the right decision for the patient nonetheless in labor management the clinical assessment still has a key role.

PRACTICE RECOMMENDATIONS

Precise assessment of onset of labor is crucial to identify any deviation from normal course.
Latent phase of labor is when there is painful uterine contraction and some cervical effacement; dilatation up to 4 cm. The duration may vary days to weeks.
The progress of first stage labor: progressive cervical dilatation 2 cm/4 h, frequency of uterine contraction, progressive descent and rotation of the head.
There is no substantial evidence to support the imaging: CT/MRI for routine pelvic assessment. Clinical trial (labor) is still accepted for pelvic assessment. Imaging may assist in decision making for labor in woman to evaluate the pelvis with history of pelvic fracture.
Monitoring of fetal heart rate should be a routine practice to ensure fetal well being during the process of labor.

CONFLICTS OF INTEREST

The author(s) of this chapter declare that they have no interests that conflict with the contents of the chapter.

Publishers’ note: We are constantly trying to update and enhance chapters in this Series. So if you have any constructive comments about this chapter please provide them to us by selecting the "Your Feedback" link in the left-hand column.

1	Kilpatrick S, Garrison E. Normal labour and delivery Normal and problem pregnancies, 7th edn., 246–9.
2	Makino S, Zaragoza D, Mitchell B, Prostaglandin F2alpha and its receptor as activators of human decidua. 2007;25:60.
3	Beshay V, Carr B, Rainey W. The human fetal adrenal gland, corticotropin-releasing hormone, and parturition. 2007;25:14.
4	Lockwood C. The initiation of parturition at term. 2004;31:935.
5	Caldeyro-Barcia R, Sica-Blanco Y, Poseiro J, A quantitative study of the action of synthetic oxytocin on the pregnant human uterus. 1957;121:18.
6	Miller F. Uterine activity, labor management, and perinatal outcome. 1978;2:181.
7	Intrapartum guideline NICE (CG190).

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Malpresentations and malpositions

Peer reviewed by Dr Laurence Knott Last updated by Dr Colin Tidy, MRCGP Last updated 22 Jun 2021

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Usually the fetal head engages in the occipito-anterior position (more often left occipito-anterior (LOA) rather than right) and then undergoes a short rotation to be directly occipito-anterior in the mid-cavity. Malpositions are abnormal positions of the vertex of the fetal head relative to the maternal pelvis. Malpresentations are all presentations of the fetus other than vertex.

Obstetrics - the pelvis and head

Continue reading below

Predisposing factors to malpresentation include:

Prematurity.

Multiple pregnancy.

Abnormalities of the uterus - eg, fibroids.

Partial septate uterus.

Abnormal fetus.

Placenta praevia.

Primiparity.

Breech presentation

See the separate Breech Presentations article for more detailed discussion.

Breech presentation is the most common malpresentation, with the majority discovered before labour. Breech presentation is much more common in premature labour.

Approximately one third are diagnosed during labour when the fetus can be directly palpated through the cervix.

After 37 weeks, external cephalic version can be attempted whereby an attempt is made to turn the baby manually by manipulating the pregnant mother's abdomen. This reduces the risk of non-cephalic delivery 1 .

Maternal postural techniques have also been tried but there is insufficient evidence to support these 2 .

Many women who have a breech presentation can deliver vaginally. Factors which make this less likely to be successful include 3 :

Hyperextended neck on ultrasound.

High estimated fetal weight (more than 3.8 kg).

Low estimated weight (less than tenth centile).

Footling presentation.

Evidence of antenatal fetal compromise.

Transverse lie 4

When the fetus is positioned with the head on one side of the pelvis and the buttocks in the other (transverse lie), vaginal delivery is impossible.

This requires caesarean section unless it converts or is converted late in pregnancy. The surgeon may be able to rotate the fetus through the wall of the uterus once the abdominal wall has been opened. Otherwise, a transverse uterine incision is needed to gain access to a fetal pole.

Internal podalic version is no longer attempted.

Transverse lie is associated with a risk of cord prolapse of up to 20%.

Occipito-posterior position

This is the most common malposition where the head initially engages normally but then the occiput rotates posteriorly rather than anteriorly. 5.2% of deliveries are persistent occipito-posterior 5 .

The occipito-posterior position results from a poorly flexed vertex. The anterior fontanelle (four radiating sutures) is felt anteriorly. The posterior fontanelle (three radiating sutures) may also be palpable posteriorly.

It may occur because of a flat sacrum, poorly flexed head or weak uterine contractions which may not push the head down into the pelvis with sufficient strength to produce correct rotation.

As occipito-posterior-position pregnancies often result in a long labour, close maternal and fetal monitoring are required. An epidural is often recommended and it is essential that adequate fluids be given to the mother.

The mother may get the urge to push before full dilatation but this must be discouraged. If the head comes into a face-to-pubis position then vaginal delivery is possible as long as there is a reasonable pelvic size. Otherwise, forceps or caesarean section may be required.

Occipito-transverse position

The head initially engages correctly but fails to rotate and remains in a transverse position.

Alternatives for delivery include manual rotation of fetal head using Kielland's forceps, or delivery using vacuum extraction. This is inappropriate if there is any fetal acidosis because of the risk of cerebral haemorrhage.

Therefore, there must be provision for a failure of forceps delivery to be changed immediately to a caesarean. The trial of forceps is therefore often performed in theatre. Some centres prefer to manage by caesarean section without trial of forceps.

Face presentations

Face presents for delivery if there is complete extension of the fetal head.

Face presentation occurs in 1 in 1,000 deliveries 5 .

With adequate pelvic size, and rotation of the head to the mento-anterior position, vaginal delivery should be achieved after a long labour.

Backwards rotation of the head to a mento-posterior position requires a caesarean section.

Brow positions

The fetal head stays between full extension and full flexion so that the biggest diameter (the mento-vertex) presents.

Brow presentation occurs in 0.14% of deliveries 5 .

Brow presentation is usually only diagnosed once labour is well established.

The anterior fontanelle and super orbital ridges are palpable on vaginal examination.

Unless the head flexes, a vaginal delivery is not possible, and a caesarean section is required.

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Mechanism of Labour

First Online: 02 August 2023

Cite this chapter

Vinayachandran S. 2 , 3 &
Sajala Vimalraj 2

716 Accesses

Labour and delivery, the process by which the mature foetus is expelled from the uterus, is not a passive process. It involves a complex interaction of uterine activity, the foetus and the maternal pelvis, to achieve a successful negotiation of this start of the human life. This chapter describes the Mechanism of Labour - the positional changes in the presenting part of the foetus to achieve a successful passage through the birth canal - with a brief look at the passenger (the foetus), the passage (the pelvis) and the powers (the uterine activity) and the complex interaction between them, resulting in the six cardinal movements – descent, flexion, internal rotation, extension, restitution and external rotation. It also gives an overview of the normal progression of Labour and the evolution from the traditional model described by Friedman to the contemporary partogram, influenced by the pioneering work of Zhang et al, according to which more time can be given to the labouring woman to achieve natural childbirth, provide maternal and foetal condition remains good. All of this has been incorporated into the WHO Labour Care Guide, designed to encourage Respectable Maternity Care. Intrapartum USG can also help guide the Obstetrician about the progress of Labour and the need for Caesarean Delivery

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S., V., Vimalraj, S. (2023). Mechanism of Labour. In: Garg, R. (eds) Labour and Delivery. Springer, Singapore. https://doi.org/10.1007/978-981-19-6145-8_2

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Face Presentation

Face it. We have a lot to learn about fetal positioning. The old paradigm is fetal positions are random. The new paradigm is that babies match the space available.

Face and brow presentations occur when baby’s spine extended until the head is shifted back so baby’s face comes through the pelvis first.

Baby may settle in a face or brow presentation before labor or they may become a face or brow presentation, usually when a posterior baby has it’s chin pushed further up by the pelvic floor during descent.

A baby who is in a face-first or forehead-first position often started as an extended (chin up) occiput posterior or occiput transverse position. Coming down on to the pelvic floor with the forehead leading then “converted” this baby’s head to the face first position.

The baby’s face may be bruised for a couple days after the birth. The brow presentation may cause a redness but only occasionally will cause a bruise.

Mobility of the pelvis and the freedom of maternal movements often help bring the face-first baby down through the pelvis with good strong, uterine surges.

But not always. Sometimes the labor can’t move baby down. Cesareans are more common, but a portion of the higher surgical rate is because time is not given to the mother to begin or continue labor, or to be out of bed for this labor. Monitoring becomes important. Expect a bit of an unusual heart rate to contraction pattern seen in these labors.

When is Breech an Issue?
Belly Mapping® Breech
Flip a Breech
When Baby Flips Head Down
Breech & Bicornuate Uterus
Breech for Providers
What if My Breech Baby Doesn't Turn?
Belly Mapping ®️ Method
After Baby Turns
Head Down is Not Enough
Sideways/Transverse
Asynclitism
Oblique Lie
Left Occiput Transverse
Right Occiput Anterior
Right Occiput Posterior
Right Occiput Transverse
Left Occiput Anterior
OP Truths & Myths
Anterior Placenta
Body Balancing

What makes labor easier for a face-first baby and you?

Balance the body and the baby will thank you by curling into position to aim, not their face, but the crown of their head.

Flexion is physiological. So support physiology and the baby will change their position. We may need a little physics.

In Labor with a Face or Brow Presentation

Back baby up!

Forward-leaning Inversion with a jiggle of the buttocks right through 1-2 contractions often backs baby up so they can tuck their chin. Then they can aim into the pelvis with an easier position.

Shake the Apples in Forward-leaning Inversion with hands

A little effort can make labor a lot easier!

Only after baby’s crown is first, then do Side-lying Release in labor.

Before Labor with a face or brow presentation

Face presentation may reflect a psoas/pelvic floor imbalance with a collapse in the front body.

Free the piriformis, strengthen the buttocks, lengthen the hamstrings, squat for lengthening the pelvic floor, don’t worry about strengthening the pelvic floor right now. Alignment, walking, stabilizing and lengthening will tone the pelvic floor. Use it by breathing with your whole body.

Before labor, it’s safe to do Side-lying Release when baby’s face-first head isn’t in the pelvis yet.

Free the way

The psoas is the upper guide, the pelvic floor is the lower guide. release spasms and lengthen both.

Make room for the baby by releasing muscles that spasm, lengthen ligaments that are shortened, and support the abdominal muscles by attending to the muscles that interact with them, don’t go directly to the front first.

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Stages of labor and birth: Baby, it's time!

Labor is a natural process. Here's what to expect during the stages of labor and birth — along with some tips to make labor more comfortable.

Labor is a unique experience. For some people, it's over in a matter of hours or less. For others, a long labor may test the limits of physical and emotional stamina.

You won't know how labor and childbirth will unfold until it happens. But you can prepare by understanding the series of events that typically takes place during labor and delivery.

Stage 1: Early labor and active labor

Cervical effacement and dilation

During the first stage of labor, the cervix opens. The medical term for this is dilation. The cervix also thins out. The medical term for this is effacement. Dilation and effacement usually happen together. This process allows the baby to move into the birth canal. In figures A and B, the cervix is tightly closed. In figure C, the cervix is 60% effaced and 1 to 2 cm dilated. In figure D, the cervix is 90% effaced and 4 to 5 cm dilated. The cervix must be 100% effaced and 10 cm dilated before a vaginal delivery.

The first stage of labor and birth happens when you begin to feel ongoing contractions. These contractions become stronger, and they happen more often as time goes on. They cause the cervix to open. This is called dilation. The contractions also soften, shorten and thin the cervix. That process is called effacement. It allows the baby to move into the birth canal.

The first stage of labor is the longest of the three stages. It's divided into two phases — early labor and active labor.

Early labor

During early labor, also called latent labor, the cervix opens and softens. It also gets shorter and thinner. The cervix opens less than 6 centimeters (cm) in early labor. Contractions tend to be mild, and they may not happen consistently.

As the cervix begins to open, you might notice a clear pink or slightly bloody discharge from your vagina. This likely is the mucus plug that blocks the cervical opening during pregnancy.

How long it lasts: Early labor isn't predictable. It may stop and start. The average length varies from hours to days. It's often shorter for people who have had a baby before.

What you can do: For many people, early labor isn't particularly uncomfortable. But contractions may be more intense for some. And sometimes contractions may continue for a long period of time during early labor. Try to stay relaxed.

The following may help keep you comfortable during early labor:

Go for a walk.
Take a shower or bath.
Listen to relaxing music.
Try breathing or relaxation techniques taught in childbirth class.
Change positions.

If your pregnancy isn't high risk, you may spend most of your early labor at home. Most of the time, pregnant people don't need to go to a hospital or birthing center until contractions start to get more intense and happen more often. Talk to your healthcare professional about when to leave for the hospital or birthing center. If your water breaks or you have a lot of vaginal bleeding, contact your healthcare professional right away.

Active labor

During active labor, the cervix opens from 6 cm to 10 cm. Contractions become stronger and closer together. They also happen more consistently. Your legs might cramp. Your stomach may feel upset. If it didn't happen earlier, you might feel your water break. You also may feel more pressure in your back. If you haven't headed to your labor and delivery facility yet, now's the time.

Your initial excitement may fade as labor goes on and you get more uncomfortable. Ask for pain medication or anesthesia if you want it. Your healthcare team works with you to make the best choice for you and your baby. Remember, you're the only one who can judge your need for pain relief.

How long it lasts: Active labor often lasts 4 to 8 hours or more. On average, the cervix opens at approximately 1 cm an hour. But it may take longer for people who haven't had a baby before.

What you can do: Look to your labor partner and healthcare team for encouragement and support. Try breathing and relaxation techniques to ease pain. Use what you learned in childbirth class or ask your healthcare team for suggestions.

Unless you need to be in a specific position to allow for close monitoring of you and your baby, try the following to be more comfortable during active labor:

Roll on a large rubber ball (birthing ball).
Take a warm shower or bath.
Take a walk, stopping to breathe through contractions.
Have a gentle massage between contractions.

If you need a Cesarean delivery, also called a C-section, having food in your stomach can lead to complications. If your healthcare professional thinks you might need a C-section, or if you have an epidural for pain relief, you may be limited to small amounts of clear liquids, such as water, ice chips, popsicles and juice, instead of solid foods.

The last part of active labor can be particularly intense and painful. Contractions come close together and can last 60 to 90 seconds. You may have pressure in your lower back and rectum. Tell a member of your healthcare team if you feel the urge to push.

If you want to push but your cervix isn't fully open, you'll likely need to wait. Pushing too soon could make you tired and cause your cervix to swell. That might delay delivery. Pant or blow through the contractions. This part of labor typically is short, lasting about 15 to 60 minutes.

Stage 2: The birth of your baby

It's time! You deliver your baby during the second stage of labor.

How long it lasts: It can take from a few minutes to a few hours to push your baby into the world. People who haven't had a baby before and those who have an epidural typically need longer to push compared to those who've had a baby or don't have an epidural.

What you can do: Push! Your healthcare professional asks you to bear down during each contraction or tells you when to push. Or you might be asked to push when you feel the urge to do so.

When it's time to push, you may experiment with different positions until you find one that feels best. You can push while squatting, sitting, kneeling — even on your hands and knees. A member of your healthcare team can check progress during pushing to help you know if your efforts are working.

At some point, you might be asked to push more gently — or not at all. Slowing down gives your vaginal tissues time to stretch rather than tear. To stay motivated, you might ask if you could feel the baby's head between your legs or see it in a mirror.

After your baby's head is delivered, the shoulders are delivered. Then the rest of the baby's body follows shortly. The baby's airway is cleared if necessary. If the delivery didn't involve any health concerns for you or your baby, your healthcare professional may wait a few seconds to a few minutes before the umbilical cord is cut. Waiting to clamp and cut the umbilical cord after delivery increases the flow of nutrient-rich blood from the cord and the placenta to the baby. This raises the baby's iron stores and lowers the risk of anemia. That helps with healthy development and growth.

Stage 3: Delivery of the placenta

After your baby is born, you'll likely feel a great sense of relief. You might hold the baby in your arms or on your belly. Cherish the moment. But there's still a little more to do. During the third stage of labor, you deliver the placenta.

How long it lasts: The placenta typically is delivered within 30 minutes.

Mild, less painful contractions that are close together continue after delivery. The contractions help move the placenta into the birth canal. You push gently one more time to deliver the placenta. You might be given medicine before or after the placenta is delivered to encourage uterine contractions and minimize bleeding.

Your healthcare professional examines the placenta to make sure it's in one piece. If any pieces of the placenta are left in the uterus, they must be removed to prevent bleeding and infection. If you're interested, ask to see the placenta.

After you deliver the placenta, your uterus continues to contract to help it return to its usual size.

A member of your healthcare team may massage your belly. This helps the uterus contract to lessen bleeding.

Your healthcare professional checks to see whether you need repair of any tears of your vaginal area. If you didn't have an epidural, you'll receive an injection of local anesthetic in the area to be repaired.

Savor this special time with your baby. Your preparation, pain and effort have paid off. Enjoy the miracle of birth.

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Funai EF, et al. Management of normal labor and delivery. https://www.uptodate.com/contents/search. Accessed Oct. 28, 2021.
Caughey AB, et al. Nonpharmacologic approaches to management of labor pain. https://www.uptodate.com/contents/search. Accessed Oct. 28, 2021.
Satin AJ. Labor: Diagnosis and management of the latent phase. https://www.uptodate.com/contents/search. Accessed Oct. 28, 2021.
American College of Obstetricians and Gynecologists. Labor and delivery. In: Your Pregnancy and Childbirth: Month to Month. Kindle edition. 7th ed. American College of Obstetricians and Gynecologists; 2021. Accessed Oct. 28, 2021.
Landon MB, et al. Normal labor and delivery. In: Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Elsevier; 2021. http://www.clinicalkey.com. Accessed Oct. 28, 2021.
Meek JY, et al. The first feedings. In: The American Academy of Pediatrics New Mother's Guide to Breastfeeding. Kindle edition. 3rd ed. Bantam Books; 2017. Accessed Oct. 28, 2021.
Cunningham FG, et al. Normal labor. In: Williams Obstetrics. 25th ed. McGraw-Hill Education; 2018. https://www.accessmedicine.mhmedical.com. Accessed Oct. 28, 2021.
Larish AM (expert opinion). Mayo Clinic. Feb. 27, 2024.

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Normal Labor and Delivery

Author: Sarah Hagood Milton, MD; Chief Editor: Christine Isaacs, MD more...
Sections Normal Labor and Delivery
Practice Essentials
Stages of Labor and Epidemiology
Mechanism of Labor
Clinical History and Physical Examination
Intrapartum Management of Labor
Pain Control
Questions & Answers

Labor is a physiologic process during which the fetus, membranes, umbilical cord, and placenta are expelled from the uterus.

Stages of labor

Obstetricians have divided labor into 3 stages that delineate milestones in a continuous process.

First stage of labor

Begins with regular uterine contractions and ends with complete cervical dilatation at 10 cm

Divided into a latent phase and an active phase

The latent phase begins with mild, irregular uterine contractions that soften and shorten the cervix

Contractions become progressively more rhythmic and stronger

The active phase usually begins at about 3-4 cm of cervical dilation and is characterized by rapid cervical dilation and descent of the presenting fetal part

Second stage of labor

Begins with complete cervical dilatation and ends with the delivery of the fetus

In nulliparous persons, the second stage should be considered prolonged if it exceeds 3 hours if regional anesthesia is administered or 2 hours in the absence of regional anesthesia

In multiparous persons, the second stage should be considered prolonged if it exceeds 2 hours with regional anesthesia or 1 hour without it [ 1 ]

Third stage of labor

The period between the delivery of the fetus and the delivery of the placenta and fetal membranes

Delivery of the placenta often takes less than 10 minutes, but the third stage may last as long as 30 minutes

Expectant management involves spontaneous delivery of the placenta

The third stage of labor is considered prolonged after 30 minutes, and active intervention is commonly considered [ 2 ]

Active management often involves prophylactic administration of oxytocin or other uterotonics (prostaglandins or ergot alkaloids), cord clamping/cutting, and controlled traction of the umbilical cord

Mechanism of labor

The mechanisms of labor, also known as the cardinal movements, involve changes in the position of the fetus’s head during its passage in labor. These are described in relation to a vertex presentation. Although labor and delivery occurs in a continuous fashion, the cardinal movements are described as the following 7 discrete sequences [ 2 ] :

Internal rotation

Restitution and external rotation.

Frequency and time of onset of contractions

Status of the amniotic membranes (whether spontaneous rupture of the membranes has occurred, and if so, whether the amniotic fluid is clear or meconium stained)

Fetal movements

Presence or absence of vaginal bleeding.

Braxton-Hicks contractions must be differentiated from true contractions. Typical features of Braxton-Hicks contractions are as follows:

Usually occur no more often than once or twice per hour, and often just a few times per day

Irregular and do not increase in frequency with increasing intensity

Resolve with ambulation or a change in activity

Contractions that lead to labor have the following characteristics:

May start as infrequently as every 10-15 minutes, but usually accelerate over time, increasing to contractions that occur every 2-3 minutes

Tend to last longer and are more intense than Braxton-Hicks contractions

Lead to cervical change

Physical examination

The physical examination should include documentation of the following:

Maternal vital signs

Fetal presentation

Assessment of fetal well-being

Frequency, duration, and intensity of uterine contractions

Abdominal examination with Leopold maneuvers

Pelvic examination with sterile gloves

Digital examination allows the clinician to determine the following aspects of the cervix:

Degree of dilatation, which ranges from 0 cm (closed or fingertip) to 10 cm (complete or fully dilated)

Effacement (assessment of the cervical length, which can be reported as a percentage of the normal 3- to 4-cm–long cervix or described as the actual cervical length)

Position (ie, anterior or posterior)

Consistency (ie, soft or firm)

Palpation of the presenting part of the fetus allows the examiner to establish its station, by quantifying the distance of the body (-5 to +5 cm) that is presenting relative to the maternal ischial spines, where 0 station is in line with the plane of the maternal ischial spines. [ 2 ]

Intrapartum management of labor

On admission to the labor and delivery suite, persons having normal labor should be encouraged to assume the position that they find most comfortable. Possibilities including the following:

Lying supine

Resting in a left lateral decubitus position

Management includes the following:

Periodic assessment of the frequency and strength of uterine contractions and changes in cervix and in the fetus' station and position

Monitoring the fetal heart rate at least every 15 minutes, particularly during and immediately after uterine contractions; in most obstetric units, the fetal heart rate is assessed continuously [ 3 ]

With complete cervical dilatation, the fetal heart rate should be monitored or auscultated at least every 5 minutes and after each contraction. [ 3 ] Prolonged duration of the second stage alone does not mandate operative delivery if progress is being made, but management options for second-stage arrest include the following:

Continuing observation/expectant management

Operative vaginal delivery by forceps or vacuum-assisted vaginal delivery, or cesarean delivery.

Delivery of the fetus

Positioning of the patient for delivery can be any of the following [ 2 ] :

Supine with the knees bent (ie, dorsal lithotomy position; the usual choice)

Lateral (Sims) position

Partial sitting or squatting position

On the hands and knees

Episiotomy used to be routinely performed at this time, but current recommendations restrict its use to maternal or fetal indications

Delivery maneuvers are as follows:

The head is held in mid position until it is delivered, followed by suctioning of the oropharynx and nares

Check the fetus's neck for a wrapped umbilical cord, and promptly reduce it if possible

If the cord is wrapped too tightly to be removed, the cord can be double clamped and cut

The fetus's anterior shoulder is delivered with gentle downward traction on its head and chin

Subsequent upward pressure in the opposite direction facilitates delivery of the posterior shoulder

The rest of the fetus should now be easily delivered with gentle traction away from the birthing parent

If not done previously, the cord is clamped and cut

The baby is vigorously stimulated and dried and then transferred to the care of the waiting attendants or placed on the birthing parent's abdomen

The following 3 classic signs indicate that the placenta has separated from the uterus [ 2 ] :

The uterus contracts and rises

The umbilical cord suddenly lengthens

A gush of blood occurs

Delivery of the placenta usually happens within 5-10 minutes after delivery of the fetus, but it is considered normal up to 30 minutes after delivery of the fetus.

Pain control

Agents given in intermittent doses for systemic pain control include the following [ 4 ] :

Meperidine, 25-50 mg IV every 1-2 hours or 50-100 mg IM every 2-4 hours

Fentanyl, 50-100 mcg IV every hour

Nalbuphine, 10 mg IV or IM every 3 hours

Butorphanol, 1-2 mg IV or IM every 4 hours

Morphine, 2-5 mg IV or 10 mg IM every 4 hours

As an alternative, regional anesthesia may be given. Anesthesia options include the following:

Combined spinal-epidural

Labor is a physiologic process during which the products of conception (ie, the fetus, membranes, umbilical cord, and placenta) are expelled outside of the uterus. Labor is achieved with changes in the biochemical connective tissue and with gradual effacement and dilatation of the uterine cervix as a result of rhythmic uterine contractions of sufficient frequency, intensity, and duration. [ 1 , 2 ]

Labor is a clinical diagnosis. The onset of labor is defined as regular, painful uterine contractions resulting in progressive cervical effacement and dilatation. Cervical dilatation in the absence of uterine contraction suggests cervical insufficiency, whereas uterine contraction without cervical change does not meet the definition of labor.

The first stage begins with regular uterine contractions and ends with complete cervical dilatation at 10 cm. In Friedman’s landmark studies of 500 nulliparas, [ 5 ] he subdivided the first stage into an early latent phase and an ensuing active phase. The latent phase begins with mild, irregular uterine contractions that soften and shorten the cervix. The contractions become progressively more rhythmic and stronger. This is followed by the active phase of labor, which usually begins at about 3-4 cm of cervical dilation and is characterized by rapid cervical dilation and descent of the presenting fetal part. The first stage of labor ends with complete cervical dilation at 10 cm. According to Friedman, the active phase is further divided into an acceleration phase, a phase of maximum slope, and a deceleration phase.

Characteristics of the average cervical dilatation curve is known as the Friedman labor curve, and a series of definitions of labor protraction and arrest were subsequently established. [ 6 , 7 ] However, subsequent data of modern obstetric population suggest that the rate of cervical dilatation is slower and the progression of labor may be significantly different from that suggested by the Friedman labor curve. [ 8 , 9 , 10 ]

The second stage begins with complete cervical dilatation and ends with the delivery of the fetus. The American College of Obstetricians and Gynecologists (ACOG) has suggested that a prolonged second stage of labor should be considered when the second stage of labor exceeds 3 hours if regional anesthesia is administered or 2 hours in the absence of regional anesthesia for nulliparas. In multiparous persons, such a diagnosis can be made if the second stage of labor exceeds 2 hours with regional anesthesia or 1 hour without it. [ 1 ]

Studies performed to examine perinatal outcomes associated with a prolonged second stage of labor revealed increased risks of operative deliveries and maternal morbidities but no differences in neonatal outcomes. [ 11 , 12 , 13 , 14 ] Maternal risk factors associated with a prolonged second stage include nulliparity, increasing maternal weight and/or weight gain, use of regional anesthesia, induction of labor, fetal occiput in a posterior or transverse position, and increased birthweight. [ 13 , 14 , 15 , 16 ]

The third stage of labor is defined by the time period between the delivery of the fetus and the delivery of the placenta and fetal membranes. During this period, uterine contraction decreases basal blood flow, which results in thickening and reduction in the surface area of the myometrium underlying the placenta with subsequent detachment of the placenta. [ 17 ] Although delivery of the placenta often requires less than 10 minutes, the duration of the third stage of labor may last as long as 30 minutes.

Expectant management of the third stage of labor involves spontaneous delivery of the placenta. Active management often involves prophylactic administration of oxytocin or other uterotonics (prostaglandins or ergot alkaloids), cord clamping/cutting, and controlled cord traction of the umbilical cord. Andersson et al found that delayed cord clamping (≥180 seconds after delivery) improved iron status and reduced prevalence of iron deficiency at age 4 months and also reduced prevalence of neonatal anemia, without apparent adverse effects. [ 18 ]

A systematic review of the literature that included 5 randomized controlled trials comparing active and expectant management of the third stage reports that active management shortens the duration of the third stage and is superior to expectant management with respect to blood loss/risk of postpartum hemorrhage; however, active management is associated with an increased risk of unpleasant side effects. [ 19 ]

The third stage of labor is considered prolonged after 30 minutes, and active intervention, such as manual extraction of the placenta, is commonly considered. [ 2 ]

Epidemiology

As the childbearing population in the United States has changed, the clinical obstetric management of labor also has evolved since Friedman's studies. Data from number a studies have suggested that normal labor can progress at a rate much slower than that Friedman and Sachtleben [ 6 , 7 ] had described. Zhang et al examined the labor progression of 1162 nulliparas who presented in spontaneous labor and constructed a labor curve that was markedly different from Friedman's: The average interval to progress from 4-10 cm of cervical dilatation was 5.5 hours compared with 2.5 hours of Friedman's labor curve. [ 20 ] Kilpatrick et al [ 8 ] and Albers et al [ 9 ] also reported that the median lengths of first and second stages of labor were longer than those Friedman suggested.

A number of investigators have identified several maternal characteristics obstetric factors that are associated with the length of labor. One group reported that increasing maternal age was associated with a prolonged second stage but not first stage of labor. [ 21 ]

While nulliparity is associated with a longer labor compared to multiparas, increasing parity does not further shorten the duration of labor. [ 22 ] Some authors have observed that the length of labor differs among racial/ethnic groups. One group reported that Asian women have the longest first and second stages of labor compared with Caucasian or African American women [ 23 ] , and American Indian women had second stages shorter than those of non-Hispanic Caucasian women. [ 9 ] However, others report conflicting findings. [ 24 , 25 ] Differences in the results may have been due to variations in study designs, study populations, labor management, or statistical power.

In one large retrospective study of the length of labor, specifically with respect to race and/or ethnicity, the authors observed no significant differences in the length of the first stage of labor among different racial/ethnic groups. However, the second stage was shorter in African American women than in Caucasian women for both nulliparas (-22 min) and multiparas (-7.5 min). Hispanic nulliparas, compared with their Caucasian counterparts, also had a shortened second stage, whereas no differences were seen for multiparas. In contrast, Asian nulliparas had a significantly prolonged second stage compared with their Caucasian counterparts, and no differences were seen for multiparas. [ 26 ]

According to a systematic review of 13 trials involving 16,242 women, most women whose prenatal and childbirth care were led by a midwife had better outcomes compared with those whose care was led by a physician or shared among disciplines. Patients who received midwife-led pregnancy care were less likely to have regional analgesia, episiotomy, and instrumental birth and more likely to have no intrapartum analgesia or anesthesia, spontaneous vaginal birth, attendance at birth by a known midwife, and a longer mean length of labor. They were also less likely to have preterm birth and fetal loss before 24 weeks' gestation. However, the average risk ratio for caesarean births did not differ between groups, and there were no differences in fetal loss/neonatal death at 24 or more weeks' gestation or in overall fetal/neonatal death. [ 1 , 27 ]

Concerns associated with midwife-attended home births

However, concerns about the effect of midwife-attended home births on neonatal health were raised by an analysis of nearly 14 million singleton, full-term births, from 2007-2010, of infants of normal weight. The data, from the National Center for Health Statistics, indicated that delivering at home was associated with a greater than 10-fold increased risk for an Apgar score of 0 and a nearly 4-fold increased risk for neonatal seizure or serious neurologic dysfunction, as compared with hospital delivery. [ 28 , 29 ]

Compared with delivery by a hospital physician, midwife-attended home birth was associated with a relative risk (RR) of 10.55 for an Apgar score of 0. For midwife deliveries at freestanding birth centers, the RR was 3.56, and for hospital midwife deliveries, the RR was 0.55. [ 28 , 29 ]

In the same study, the RR for neonatal seizures or serious neurologic disorders for midwife-attended home births, compared with physician-attended hospital delivery, was 3.80. Compared with in-hospital physician delivery, the RR for midwife delivery at freestanding birth centers was 1.88, and for hospital midwife delivery, the RR was 0.74. [ 28 , 29 ]

The ability of the fetus to successfully negotiate the pelvis during labor involves changes in position of its head during its passage in labor. The mechanisms of labor, also known as the cardinal movements, are described in relation to a vertex presentation, as is the case in 95% of all pregnancies. Although labor and delivery occurs in a continuous fashion, the cardinal movements are described as 7 discrete sequences, as discussed below. [ 2 ]

The widest diameter of the presenting part (with a well-flexed head, where the largest transverse diameter of the fetal occiput is the biparietal diameter) enters the maternal pelvis to a level below the plane of the pelvic inlet. On the pelvic examination, the presenting part is at 0 station, or at the level of the maternal ischial spines.

The downward passage of the presenting part through the pelvis. This occurs intermittently with contractions. The rate is greatest during the second stage of labor.

As the fetal vertex descents, it encounters resistance from the bony pelvis or the soft tissues of the pelvic floor, resulting in passive flexion of the fetal occiput. The chin is brought into contact with the fetal thorax, and the presenting diameter changes from occipitofrontal (11.0 cm) to suboccipitobregmatic (9.5 cm) for optimal passage through the pelvis.

As the head descends, the presenting part, usually in the transverse position, is rotated about 45° to anteroposterior (AP) position under the symphysis. Internal rotation brings the AP diameter of the head in line with the AP diameter of the pelvic outlet.

With further descent and full flexion of the head, the base of the occiput comes in contact with the inferior margin of the pubic symphysis. Upward resistance from the pelvic floor and the downward forces from the uterine contractions cause the occiput to extend and rotate around the symphysis. This is followed by the delivery of the fetus' head.

When the fetus' head is free of resistance, it untwists about 45° left or right, returning to its original anatomic position in relation to the body.

After the fetus' head is delivered, further descent brings the anterior shoulder to the level of the pubic symphysis. The anterior shoulder is then rotated under the symphysis, followed by the posterior shoulder and the rest of the fetus.

The initial assessment of labor should include a review of the patient's prenatal care, including confirmation of the estimated date of delivery. Focused history taking should be conducted to include information, such as the frequency and time of onset of contractions, the status of the amniotic membranes (whether spontaneous rupture of the membranes has occurred, and if so, whether the amniotic fluid is clear or meconium stained), the fetus' movements, and the presence or absence of vaginal bleeding.

Braxton-Hicks contractions, which are often irregular and do not increase in frequency with increasing intensity, must be differentiated from true contractions. Braxton-Hicks contractions often resolve with ambulation or a change in activity. However, contractions that lead to labor tend to last longer and are more intense, leading to cervical change. True labor is defined as uterine contractions leading to cervical changes. If contractions occur without cervical changes, it is not labor. Other causes for the cramping should be diagnosed. Gestational age is not a part of the definition of labor.

In addition, Braxton-Hicks contractions occur occasionally, usually no more than 1-2 per hour, and they often occur just a few times per day. Labor contractions are persistent, they may start as infrequently as every 10-15 minutes, but they usually accelerate over time, increasing to contractions that occur every 2-3 minutes.

Patients may also describe what has been called lightening, ie, physical changes felt because the fetus' head is advancing into the pelvis. The patient may feel that the baby has become light. As the presenting fetal part starts to drop, the shape of the patient's abdomen may change to reflect descent of the fetus. Breathing may be relieved because tension on the diaphragm is reduced, whereas urination may become more frequent due to the added pressure on the urinary bladder.

Physical examination should include documentation of the patient's vital signs, the fetus' presentation, and assessment of the fetal well-being. The frequency, duration, and intensity of uterine contractions should be assessed, particularly the abdominal and pelvic examinations in patients who present in possible labor.

Abdominal examination begins with the Leopold maneuvers described below [ 2 ] :

The initial maneuver involves the examiner placing both of his or her hands on each upper quadrant of the patient's abdomen and gently palpating the fundus with the tips of the fingers to define which fetal pole is present in the fundus. If it is the fetus' head, it should feel hard and round. In a breech presentation, a large, nodular body is felt.

The second maneuver involves palpation in the paraumbilical regions with both hands by applying gentle but deep pressure. The purpose is to differentiate the fetal spine (a hard, resistant structure) from its limbs (irregular, mobile small parts) to determinate the fetus' position.

The third maneuver is suprapubic palpation by using the thumb and fingers of the dominant hand. As with the first maneuver, the examiner ascertains the fetus' presentation and estimates its station. If the presenting part is not engaged, a movable body (usually the fetal occiput) can be felt. This maneuver also allows for an assessment of the fetal weight and of the volume of amniotic fluid.

The fourth maneuver involves palpation of bilateral lower quadrants with the aim of determining if the presenting part of the fetus is engaged in the patient's pelvis. The examiner stands facing the patient's feet. With the tips of the first 3 fingers of both hands, the examiner exerts deep pressure in the direction of the axis of the pelvic inlet. In a cephalic presentation, the fetus' head is considered engaged if the examiner's hands diverge as they trace the fetus' head into the pelvis.

Pelvic examination is often performed using sterile gloves to decrease the risk of infection. If membrane rupture is suspected, examination with a sterile speculum is performed to visually confirm pooling of amniotic fluid in the posterior fornix. The examiner also looks for fern on a dried sample of the vaginal fluid under a microscope and checks the pH of the fluid by using a nitrazine stick or litmus paper, which turns blue if the amniotic fluid is alkalotic. If frank bleeding is present, pelvic examination should be deferred until placenta previa is excluded with ultrasonography. Furthermore, the pattern of contraction and the patient's presenting history may provide clues about placental abruption.

Digital examination of the vagina allows the clinician to determine the following: (1) the degree of cervical dilatation, which ranges from 0 cm (closed or fingertip) to 10 cm (complete or fully dilated), (2) the effacement (assessment of the cervical length, which is can be reported as a percentage of the normal 3- to 4-cm-long cervix or described as the actual cervical length); actual reporting of cervical length may decrease potential ambiguity in percent-effacement reporting, (3) the position, ie, anterior or posterior, and (4) the consistency, ie, soft or firm. Palpation of the presenting part of the fetus allows the examiner to establish its station, by quantifying the distance of the body (-5 to +5 cm) that is presenting relative to the maternal ischial spines, where 0 station is in line with the plane of the maternal ischial spines). [ 2 ]

The pelvis can also be assessed either by clinical examination (clinical pelvimetry) or radiographically (CT or MRI). The pelvic planes include the following:

Pelvic inlet: The obstetrical conjugate is the distance between the sacral promontory and the inner pubic arch; it should measure 11.5 cm or more. The diagonal conjugate is the distance from the undersurface of the pubic arch to sacral promontory; it is 2 cm longer than the obstetrical conjugate. The transverse diameter of the pelvic inlet measures 13.5 cm.

Midpelvis: The midpelvis is the distance between the bony points of ischial spines, and it typically exceeds 12 cm.

Pelvic outlet: The pelvic outlet is the distance between the ischial tuberosities and the pubic arch. It usually exceeds 10 cm.

The shape of the patient's pelvis can also be assessed and classified into 4 broad categories based on the descriptions of Caldwell and Moloy: gynecoid, anthropoid, android, and platypelloid. [ 30 ] Although the gynecoid and anthropoid pelvic shapes are thought to be most favorable for vaginal delivery, many patients can be classified into 1 or more pelvic types, and such distinctions can be arbitrary. [ 2 ]

High-risk pregnancies can account for up to 80% of all perinatal morbidity and mortality. The remaining perinatal complications arise in pregnancies without identifiable risk factors for adverse outcomes. [ 31 ] Therefore, all pregnancies require a thorough evaluation of risks and close surveillance. As soon as the patient arrives at the labor and delivery suite, external tocometric monitoring for the onset and duration of uterine contractions and use of a Doppler device to detect fetal heart tones and rate should be started.

In the presence of labor progression, monitoring of uterine contractions by external tocodynamometry is often adequate. However, if a laboring person is confirmed to have rupture of the membranes and if the intensity/duration of the contractions cannot be adequately assessed, an intrauterine pressure catheter can be inserted into the uterine cavity past the fetus to determine the onset, duration, and intensity of the contractions. Because the external tocometer records only the timing of contractions, an intrauterine pressure catheter can be used to measure the intrauterine pressure generated during uterine contractions if their strength is a concern. While it is considered safe, placental abruption has been reported as a rare complication of an intrauterine pressure catheter placed extramembraneously. [ 32 , 33 ]

Bedside ultrasonography may be used to assess the risk of gastric content aspiration in pregnant persons during labor, by measuring the antral cross-sectional area (CSA), according to a study by Bataille et al. [ 34 , 35 ] In the report, which involved 60 women in labor who were under epidural analgesia, the investigators found that at epidural insertion, half of the women had an antral CSA of over 320 mm 2 , indicating that they were at increased risk of gastric content aspiration while under anesthesia. [ 34 , 35 ]

It was also found that the antral CSA was reduced during labor, falling from a median of 319 mm 2 at epidural insertion to 203 mm 2 at full cervical dilatation, with only 13% of the women at that time still considered at risk of aspiration. [ 34 , 35 ] This change, according to the investigators, suggested that even under epidural anesthesia, gastric motility is preserved.

Often, fetal monitoring is achieved using cardiotography, or electronic fetal monitoring. Cardiotography as a form of fetal assessment in labor was reviewed using randomized and quasirandomized controlled trials involving a comparison of continuous cardiotocography with no monitoring, intermittent auscultation, or intermittent cardiotocography. This review concluded that continuous cardiotocography during labor is associated with a reduction in neonatal seizures but not cerebral palsy or infant mortality; however, continuous monitoring is associated with increased cesarean and operative vaginal deliveries. [ 36 ]

If nonreassuring fetal heart rate tracings by cardiotography (eg, late decelerations) are noted, a fetal scalp electrode may be applied to generate sensitive readings of beat-to-beat variability. However, a fetal scalp electrode should be avoided if the birthing parent has HIV, hepatitis B or hepatitis C infections, or if fetal thrombocytopenia is suspected. A framework has been suggested to classify and standardize the interpretation of a fetal heart rate monitoring pattern according to the risk of fetal acidemia with the intention of minimizing neonatal acidemia without excessive obstetric intervention. [ 37 ]

The question of whether fetal pulse oximetry may be useful for fetal surveillance in labor was examined in a review of 5 published trials comparing fetal pulse oximetry and cardiotography with cardiotography alone. It concluded that existing data provide limited support for the use of fetal pulse oximetry when used in the presence of a nonreassuring fetal heart rate tracing to reduce caesarean delivery for nonreassuring fetal status. The addition of fetal pulse oximetry does not reduce overall caesarean deliveries. [ 38 ]

Further evaluation of a fetus at risk for labor intolerance or distress can be accomplished with blood sampling from fetal scalp capillaries. This procedure allows for a direct assessment of fetal oxygenation and blood pH. A pH of < 7.20 warrants further investigation for the fetus' well-being and for possible resuscitation or surgical intervention.

Routine laboratory studies of the parturient, such as complete blood cell (CBC) count, blood typing and screening, and urinalysis, are usually performed. Intravenous (IV) access is established.

Cervical change occurs at a slow, gradual pace during the latent phase of the first stage of labor. Latent phase of labor is complex and not well-studied since determination of onset is subjective and may be challenging as women present for assessment at different time duration and cervical dilation during labor. In a cohort of women undergoing induction of labor, the median duration of latent labor was 384 min with an interquartile range of 240-604 min. The authors report that cervical status at admission for labor induction, but not other risk factors typically associated with cesarean delivery , is associated with length of the latent phase. [ 39 ]

Most patients experience onset of labor without premature rupture of the membranes (PROM); however, approximately 8% of term pregnancies is complicated by PROM. Spontaneous onset of labor usually follows PROM such that 50% of women with PROM who were expectantly managed delivered within 5 hours, and 95% gave birth within 28 hours of PROM. [ 40 ] The American College of Obstetricians and Gynecologists (ACOG) recommends that fetal heart rate monitoring should be used to assess fetal status and dating criteria reviewed, and group B streptococcal prophylaxis be given based on prior culture results or risk factors of cultures not available. Additionally, randomized controlled trials to date suggest that for women with PROM at term, labor induction, usually with oxytocin infusion, at time of presentation can reduce the risk of chorioamnionitis. [ 41 ]

According to Friedman and colleagues, [ 6 ] the rate of cervical dilation should be at least 1 cm/h in a nulliparous woman and 1.2 cm/h in a multiparous woman during the active phase of labor. However, labor management has changed substantially during the last quarter century. Particularly, obstetric interventions such as induction of labor, augmentation of labor with oxytocin administration, use of regional anesthesia for pain control, and continuous fetal heart rate monitoring are increasingly common practice in the management of labor in today’s obstetric population. [ 42 , 43 , 20 ] Vaginal breech and mid- or high- forceps deliveries are now rarely performed. [ 44 , 45 , 46 ] Therefore, subsequent authors have suggested normal labor may precede at a rate less rapid than those previously described. [ 8 , 9 , 20 ]

Data collected from the Consortium on Safe Labor suggests that allowing labor to continue longer before 6-cm dilation may reduce the rate of intrapartum and subsequent cesarean deliveries in the United States. [ 47 ] In the study, the authors noted that the 95 th percentile for advancing from 4-cm dilation to 5-cm dilation was longer than 6 hours; and the 95 th percentile for advancing from 5-cm dilation to 6-cm dilation was longer than 3 hours, regardless of the patient’s parity.

On admission to the labor and delivery suite, a person having normal labor should be encouraged to assume the position that is most comfortable. Possibilities including walking, lying supine, sitting, or resting in a left lateral decubitus position. Of note, ambulating during labor did not change the progression of labor in a large randomized controlled study of >1000 women in active labor. [ 48 ]

The patient and family or support team should be consulted regarding the risks and benefits of various interventions, such as the augmentation of labor using oxytocin, artificial rupture of the membranes, methods and pharmacologic agents for pain control, and operative vaginal delivery (including forceps or vacuum-assisted vaginal deliveries ) or cesarean delivery. They should be actively involved, and their preferences should be considered in the management decisions made during labor and delivery. [ 2 ]

The frequency and strength of uterine contractions and changes in cervix and in the fetus' station and position should be assessed periodically to evaluate the progression of labor. Although progression must be monitored, vaginal examinations should be performed only when necessary to minimize the risk of chorioamnionitis, particularly in patients whose amniotic membrane has ruptured. During the first stage of labor, fetal well-being can be assessed by monitoring the fetal heart rate at least every 15 minutes, particularly during and immediately after uterine contractions. In most labor and delivery units, the fetal heart rate is assessed continuously. [ 3 ]

Two methods of augmenting labor have been established. The traditional method involves the use of low doses of oxytocin with long intervals between dose increments. For example, low-dose infusion of oxytocin is started at 1 mili IU/min and increased by 1-2 mili IU/min every 20-30 minutes until adequate uterine contraction is obtained. [ 2 ]

The second method, or active management of labor, involves a protocol of clinical management that aims to optimize uterine contractions and shorten labor. This protocol includes strict criteria for admission to the labor and delivery unit, early amniotomy, hourly cervical examinations, early diagnosis of inefficient uterine activity (if the cervical dilation rate is < 1.0 cm/h), and high-dose oxytocin infusion if uterine activity is inefficient. Oxytocin infusion starts at 4 mili IU/min (or even 6 mili IU/min) and increases by 4 mili IU/min (or 6 mili IU/min) every 15 minutes until a rate of 7 contractions per 15 minutes is achieved or until the maximum infusion rate of 36 mili IU/min is reached. [ 49 , 2 ]

ACOG recommends amniotomy for patients undergoing augmentation or induction of labor to shorten the duration of labor. Additionally, either low- or high-dose oxytocin administration can be used for the active management of labor to reduce operative deliveries. [ 50 ]

Although active management of labor was originally intended to shorten the length of labor in nulliparous women, its application at the National Maternity Hospital in Dublin produced a primary cesarean delivery rate of 5-6% in nulliparas. [ 51 ] Data from randomized controlled trials confirmed that active management of labor shortens the first stage of labor and reduces the likelihood of maternal febrile morbidity, but it does not consistently decrease the probability of cesarean delivery. [ 52 , 53 , 54 ]

Although the active management protocol likely leads to early diagnosis and interventions for labor dystocia, a number of risk factors are associated with a failure of labor to progress during the first stage. These risk factors include premature rupture of the membranes (PROM), nulliparity, induction of labor, increasing maternal age, and or other complications (eg, previous perinatal death, pregestational or gestational diabetes mellitus, hypertension, infertility treatment). [ 55 , 56 ]

While the ACOG defines labor dystocia as abnormal labor that results form abnormalities of the power (uterine contractions or maternal expulsive forces), the passenger (position, size, or presentation of the fetus), or the passage (pelvis or soft tissues), labor dystocia can rarely be diagnosed with certainty. [ 1 , 50 ] Often, a "failure to progress" in the first stage is diagnosed if uterine contraction pattern exceeds 200 Montevideo units for 2 hours without cervical change during the active phase of labor is encountered. [ 1 ] Thus, the traditional criteria to diagnose active-phase arrest are cervical dilatation of at least 4 cm, cervical changes of < 1 cm in 2 hours, and a uterine contraction pattern of >200 Montevideo units. These findings are also a common indication for cesarean delivery.

Proceeding to cesarean delivery in this setting, or the "2-hour rule," was challenged in a clinical trial of 542 women with active phase arrest. [ 57 ] In this cohort of women diagnosed with active phase arrest, oxytocin was started, and cesarean delivery was not performed for labor arrest until adequate uterine contraction lasted at least 4 hours (>200 Montevideo units) or until oxytocin augmentation was given for 6 hours if this contraction pattern could not be achieved. This protocol achieved vaginal delivery rates of 56-61% in nulliparas and 88% in multiparas without severe adverse maternal or neonatal outcomes. Therefore, extending the criteria for active-phase labor arrest from 2 to at least 4 hours appears to be effective in achieving vaginal birth. [ 57 , 1 ]

When the patient enters the second stage of labor with complete cervical dilatation, the fetal heart rate should be monitored or auscultated at least every 5 minutes and after each contraction during the second stage. [ 3 ] Although the parturient may be encouraged to actively push in concordance with the contractions during the second stage, many persons with epidural anesthesia who do not feel the urge to push may allow the fetus to descend passively, with a period of rest before active pushing begins.

A number of randomized controlled trials have shown that, in nulliparous women, delayed pushing, or passive descend, is not associated with adverse perinatal outcomes or an increased risk for operative deliveries despite an often prolonged second stage of labor. [ 58 , 59 , 40 ] Furthermore, investigators who compared obstetric outcomes associated with coached versus uncoached pushing during the second stage reported a slightly shortened second stage (13 min) in the coached group, with no differences in the immediate maternal or neonatal outcomes. [ 60 ]

Le Ray et al reported that manual rotation of fetuses who were in occiput posterior or occiput transverse position at full dilatation was associated with reduced rates of operative delivery (ie, cesarean or instrumental vaginal delivery). [ 61 , 62 ] In a study involving 2 French hospitals, operative delivery rates were significantly lower at the institution whose policy favored manual rotation than at the one that favored modification of maternal position (23.2% vs 38.7%), mainly because of lower rates of instrumental deliveries (15.0% vs 28.8%).

When a prolonged second stage of labor is encountered, clinical assessment of the parturient, the fetus, and the expulsive forces is warranted. A randomized controlled trial performed by Api et al determined that application of fundal pressure on the uterus does not shorten the second stage of labor. [ 63 ] Although the 2003 ACOG practice guidelines state that the duration of the second stage alone does not mandate intervention by operative vaginal delivery or cesarean delivery if progress is being made, the clinician has several management options (continuing observation/expectant management, operative vaginal delivery by forceps or vacuum-assisted vaginal delivery, or cesarean delivery) when second-stage arrest is diagnosed.

The association between a prolonged second stage of labor and adverse maternal or neonatal outcome has been examined. While a prolonged second stage is not associated with adverse neonatal outcomes in nulliparas, possibly because of close fetal surveillance during labor, but it is associated with increased maternal morbidity, including higher likelihood of operative vaginal delivery and cesarean delivery, postpartum hemorrhage, third- or fourth-degree perineal lacerations, and peripartum infection. [ 11 , 12 , 13 , 14 ] Therefore, it is crucial to weigh the risks of operative delivery against the potential benefits of continuing labor in hopes to achieve vaginal delivery. The question of when to intervene should involve a thorough evaluation of the ongoing risks of further expectant management versus the risks of intervention with vaginal or cesarean delivery, as well as the patients' preferences.

When delivery is imminent, the patient is usually positioned supine with her knees bent (ie, dorsal lithotomy position), though delivery can occur with the patient in any position, including the lateral (Sims) position, the partial sitting or squatting position, or on her hands and knees. [ 2 ] Although an episiotomy (an incision continuous with the vaginal introitus) used to be routinely performed at this time, the ACOG recommended in 2006 that its use be restricted to maternal or fetal indications. Studies have also shown that routine episiotomy does not decrease the risk of severe perineal lacerations during forceps or vacuum-assisted vaginal deliveries. [ 64 , 65 ]

Crowning is the word used to describe when the fetal head forcibly extends the vaginal outlet. A modified Ritgen maneuver can be performed to deliver the head. Draped with a sterile towel, the heel of the clinician's hand is placed over the posterior perineum overlying the fetal chin, and pressure is applied upward to extend the fetus' head. The other hand is placed over the fetus' occiput, with pressure applied downward to flex its head. Thus, the head is held in mid position until it is delivered, followed by suctioning of the oropharynx and nares. Check the fetus' neck for a wrapped umbilical cord, and promptly reduce it if possible. If the cord is wrapped too tightly to be removed, the cord can be double clamped and cut. Of note, some providers, in an attempt to avoid shoulder dystocia, deliver the anterior shoulder prior to restitution of the fetal head.

Next, the fetus' anterior shoulder is delivered with gentle downward traction on its head and chin. Subsequent upward pressure in the opposite direction facilitates delivery of the posterior shoulder. The rest of the fetus should now be easily delivered with gentle traction away from the birthing parent. If not done previously, the cord is clamped and cut. The baby is vigorously stimulated and dried and then transferred to the care of the waiting attendants or placed on the birthing parent's abdomen.

Third stage of labor - Delivery of the placenta and the fetal membranes

The labor process has now entered the third stage, ie, delivery of the placenta. Three classic signs indicate that the placenta has separated from the uterus: (1) The uterus contracts and rises, (2) the cord suddenly lengthens, and (3) a gush of blood occurs. [ 2 ]

Delivery of the placenta usually happens within 5-10 minutes after delivery of the fetus, but it is considered normal up to 30 minutes after delivery of the fetus. Excessive traction should not be applied to the cord to avoid inverting the uterus, which can cause severe postpartum hemorrhage and is an obstetric emergency. The placenta can also be manually separated by passing a hand between the placenta and uterine wall. After the placenta is delivered, inspect it for completeness and for the presence of 1 umbilical vein and 2 umbilical arteries. Oxytocin can be administered throughout the third stage to facilitate placental separation by inducing uterine contractions and to decrease bleeding.

Expectant management of the third stage involves allowing the placenta to deliver spontaneously, whereas active management involves administration of uterotonic agent (usually oxytocin, an ergot alkaloid, or prostaglandins) before the placenta is delivered. This is done with early clamping and cutting of the cord and with controlled traction on the cord while placental separation and delivery are awaited.

A review of 5 randomized trials comparing active versus expectant management of the third stage demonstrated that active management was associated with lowered risks of maternal blood loss, postpartum hemorrhage, and prolongation of the third stage, but it increased maternal nausea, vomiting, and blood pressure (when ergometrine was used). However, given the reduced risk of complications, this review recommends that active management is superior to expectant management and should be the routine management of choice. [ 19 ]

A multicenter, randomized, controlled trial of the efficacy of misoprostol (prostaglandin E1 analog) compared with oxytocin showed that oxytocin 10 IU IV or given intramuscularly (IM) was preferable to oral misoprostol 600 mcg for active management of the third stage of labor in hospital settings. [ 66 ] Therefore, if the risks and benefits are balanced, active management with oxytocin may be considered a part of routine management of the third stage. A study by Adnan et al that included 1075 women to compare intravenous oxytocin and intramuscular oxytocin for the third stage of labor reported that although intravenous oxytocin did not lower the incidence of standard postpartum hemorrhage, it significantly lowered the incidence of severe postpartum hemorrhage as well as lowering the frequency of blood transfusion and admission to a high dependency unit. [ 67 ]

After the placenta is delivered, the labor and delivery period is complete. Palpate the patient's abdomen to confirm reduction in the size of the uterus and its firmness. Ongoing blood loss and a boggy uterus suggest uterine atony. A thorough examination of the birth canal, including the cervix and the vagina, the perineum, and the distal rectum, is warranted, and repair of episiotomy or perineal/vaginal lacerations should be carried out.

Franchi et al found that topically applied lidocaine-prilocaine (EMLA) cream was an effective and satisfactory alternative to mepivacaine infiltration for pain relief during perineal repair. In a randomized trial of 61 women with either an episiotomy or a perineal laceration after vaginal delivery, women in the EMLA group had lower pain scores than those in the mepivacaine group (1.7 +/- 2.4 vs 3.9 +/- 2.4; P = .0002), and a significantly higher proportion of women expressed satisfaction with anesthesia method in the EMLA group than in the mepivacaine group (83.8% vs 53.3%; P = .01). [ 68 ]

In a Cochrane review, Aasheim et al suggest that evidence is sufficient to support the use of warm compresses to prevent perineal tears. They also found a reduction in third-degree and fourth-degree tears with massage of the perineum to reduce the rate of episiotomy. [ 69 ]

The World Health Organization developed a checklist to address the major causes of maternal death (hemorrhage, infection, obstructed labor and hypertensive disorders), intrapartum-related stillbirths (inadequate intrapartum care), and neonatal deaths (birth asphyxia, infection and complications related to prematurity). [ 70 , 71 ]

Laboring patients often experience intense pain. Uterine contractions result in visceral pain, which is innervated by T10-L1. While in descent, the fetus' head exerts pressure on the pelvic floor, vagina, and perineum, causing somatic pain transmitted by the pudendal nerve (innervated by S2-4). [ 4 ] Therefore, optimal pain control during labor should relieve both sources of pain.

A number of opioid agonists and opioid agonist-antagonists can be given in intermittent doses for systemic pain control. These include meperidine 25-50 mg IV every 1-2 hours or 50-100 mg IM every 2-4 hours, fentanyl 50-100 mcg IV every hour, nalbuphine 10 mg IV or IM every 3 hours, butorphanol 1-2 mg IV or IM every 4 hours, and morphine 2-5 mg IV or 10 mg IM every 4 hours. [ 4 ] As an alternative, regional anesthesia may be given. Options are epidural, spinal, or combined spinal epidural anesthesia. These provide partial to complete blockage of pain sensation below T8-10, with various degree of motor blockade. These blocks can be used during labor and for surgical deliveries.

Studies performed to compare the analgesic effect of regional anesthesia and parenteral agents showed that regional anesthesia provides superior pain relief. [ 72 , 45 , 73 ] Although some researchers reported that epidural anesthesia is associated with a slight increase in the duration of labor and in the rate of operative vaginal delivery, [ 74 , 75 ] large randomized controlled studies did not reveal a difference in frequency of cesarean delivery between women who received parenteral analgesics compared with women who received epidural anesthesia [ 72 , 73 , 75 , 76 , 77 ] given during early-stage or later in labor. [ 78 ]

Additionally, an analysis of studies published since 2005 in a Cochrane review showed epidural analgesia was not associated with an increase in the rate of assisted vaginal delivery. [ 76 , 77 ] Although regional anesthesia is effective as a method of pain control, common adverse effects include maternal hypotension, maternal temperature >100.4°F, postdural puncture headache, transient fetal heart deceleration, and pruritus (with added opioids). [ 4 ]

Despite the many methods available for analgesia and anesthesia to manage labor pain, some persons may not wish to use conventional pain medications during labor, opting instead for a natural childbirth. Although these patients may use breathing and mental exercises to help alleviate labor pain, they should be assured that pain relief can be administered at any time during labor.

A Cochrane review update concluded that relaxation techniques and yoga may offer some relief and improve management of pain. Studies in the review noted increased satisfaction with pain relief and lower assisted vaginal delivery rates with relaxation techniques. One trial involving yoga noted reduced pain, increased satisfaction with pain relief, increased satisfaction with the childbirth experience, and reduced length of labor. [ 79 ]

Of note, use of nonsteroidal anti-inflammatory drugs (NSAIDs) are relatively contraindicated in the third trimester of pregnancy. The repeated use of NSAIDs has been associated with early closure of the fetal ductus arteriosus in utero and with decreasing fetal renal function leading to oligohydramnios.

ACOG made the following recommendations concerning delivery of a newborn with meconium-stained amniotic fluid [ 80 ] :

Infants with meconium-stained amniotic fluid should no longer routinely receive intrapartum suctioning. However, a team with full resuscitation skills that include endotracheal intubation should be available.
The same procedures for resuscitation for infants with clear fluid should be followed for infants with meconium-stained fluid.

What is labor?

How many stages of labor are there?

How is the first stage of labor characterized?

How is the second stage of labor characterized?

How is the third stage of labor characterized?

How are the cardinal movements of labor characterized?

What is included in the initial assessment of labor?

What are Braxton-Hicks labor contractions?

What are the characteristics of contractions that lead to labor?

What is included in the physical exam for evaluation of normal labor?

What is the role of a digital exam in the evaluation of normal labor?

How should a woman be positioned during the first stage of labor?

What monitoring is performed during the first stage of labor?

What are the options for management of a prolonged second stage of labor?

How is the mother positioned for delivery?

What maneuvers are used in the delivery of a fetus?

What are the classic signs of placenta separation from the uterus during labor?

How is pain managed during labor?

What are the local anesthesia options for normal labor and delivery?

How is labor defined?

What do the stages of labor delineate?

What is the first stage of labor?

What is the second stage of labor?

Which factors increase the risk for a prolonged second stage of labor?

What is the third stage of labor?

What is the difference between expectant and active management of the third stage of labor?

What are the benefits of active management of the third stage of labor?

How is a prolonged third stage of labor managed?

What is the average interval of the first and second stages of labor?

Which factors are associated with longer labor?

What maternal outcomes have been reported for midwife led labor and delivery?

What fetal outcomes have been reported for midwife-attended home labor and delivery?

What are the mechanisms of labor?

How is engagement during labor defined?

How is descent during labor defined?

How is flexion during labor defined?

How is internal rotation during labor defined?

How is extension during labor defined?

How is external rotation during labor defined?

How is expulsion during labor defined?

Which clinical history findings are characteristic of labor?

How is abdominal exam performed to evaluate normal labor?

How is a pelvic exam performed to evaluate normal labor?

Why is a digital exam performed in the evaluation of normal labor?

What is the anatomy of the pelvis relevant to labor and delivery?

What is the initial monitoring performed when a woman is in labor?

When is an intrauterine pressure catheter indicated for monitoring of women in labor?

What is the role of bedside ultrasonography in the monitoring of women in labor?

How is fetal monitoring performed during labor?

How is the first-stage of labor managed?

How is labor augmented?

What are the reported outcomes for active management of the first stage of labor?

Which factors increase the risk of failure to progress during the first stage of labor?

What is labor dystocia and how is it diagnosed and managed?

How is second-stage of labor managed?

How is prolonged second-stage labor managed?

What are the steps in the delivery of a fetus?

How is the third-stage of labor managed?

What is included in maternal care following the delivery of the placenta?

What is the role of pain management during labor and delivery?

What are the ACOG recommendations for the delivery of a newborn with meconium-stained amniotic fluid?

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Contributor Information and Disclosures

Sarah Hagood Milton, MD Resident Physician, Department of Obstetrics and Gynecology, Virginia Commonwealth University Health System Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference Disclosure: Received salary from Medscape for employment. for: Medscape.

A David Barnes, MD, MPH, PhD, FACOG Consulting Staff, Department of Obstetrics and Gynecology, Mammoth Hospital (Mammoth Lakes, CA), Pioneer Valley Hospital (Salt Lake City, UT), Warren General Hospital (Warren, PA), and Mountain West Hospital (Tooele, UT) A David Barnes, MD, MPH, PhD, FACOG is a member of the following medical societies: American College of Forensic Examiners Institute , American College of Obstetricians and Gynecologists , The Society of Federal Health Professionals (AMSUS) , American Medical Association , Utah Medical Association Disclosure: Nothing to disclose.

Christine Isaacs, MD Associate Professor, Department of Obstetrics and Gynecology, Division Head, General Obstetrics and Gynecology, Medical Director of Midwifery Services, Virginia Commonwealth University School of Medicine Christine Isaacs, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists Disclosure: Nothing to disclose.

Bruce A Meyer, MD, MBA Executive Vice President for Health System Affairs, Executive Director, Faculty Practice Plan, Professor, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical School Bruce A Meyer, MD, MBA is a member of the following medical societies: Medical Group Management Association , American College of Obstetricians and Gynecologists , American Association for Physician Leadership , American Institute of Ultrasound in Medicine , Association of Professors of Gynecology and Obstetrics , Massachusetts Medical Society , Society for Maternal-Fetal Medicine Disclosure: Nothing to disclose.

Aaron B Caughey, MD, MPH, PhD Department Chair, Department of Obstetrics and Gynecology, Julie Newpert Stott Director of Center for Women's Health, Oregon Health and Science University School of Medicine Aaron B Caughey, MD, MPH, PhD is a member of the following medical societies: American College of Obstetricians and Gynecologists , Society for Maternal-Fetal Medicine , Society for Medical Decision Making , Society for Reproductive Investigation Disclosure: Nothing to disclose.

Yvonne Cheng, MD, MPH Adjunct Assistance Professor, Division of Maternal-Fetal Medicine, Departments of Obstetrics, Gynecology and Reproductive Science, University of California at San Francisco School of Medicine Yvonne Cheng, MD, MPH is a member of the following medical societies: American College of Obstetricians and Gynecologists , American Medical Association , Society for Maternal-Fetal Medicine Disclosure: Nothing to disclose.

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors Faraaz Omar Khan, MD, and Mahpara Syed Razi, MD, to the development and writing of this article.

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BMJ Case Rep

Cord presentation in labour: imminent risk of cord prolapse

Tiago aguiar.

1 Gynaecology Department, Centro Hospitalar Universitário São João, Porto, Portugal

2 Obstetrics Department, Centro Hospitalar Universitário São João, Porto, Portugal

João Cavaco Gomes

Teresa rodrigues, description.

A 37-year-old pregnant woman at 39 weeks of gestation, gravida 3, para 2, with a history of uncomplicated spontaneous vaginal deliveries at term, presented to the emergency department with lower abdominal cramps and watery vaginal discharge that started 2 hours before. Vaginal examination confirmed ruptured membranes, 3 cm cervical dilation, 30% effacement, and a mass of umbilical cord loops was presenting. Transvaginal ultrasound demonstrated an agglomerate of umbilical cord loops lying between the internal os and the fetal head ( figures 1 and 2 ). Due to the imminent possibility of overt cord prolapse, an emergent caesarean section was performed, with the delivery of a newborn weighing 3640 g, Apgar score 9 at 1 min and 10 at 5 min.

An external file that holds a picture, illustration, etc.
Object name is bcr-2021-243320f01.jpg

Transvaginal ultrasound showing the umbilical cord between the fetal head and the cervix.

An external file that holds a picture, illustration, etc.
Object name is bcr-2021-243320f02.jpg

Transvaginal ultrasound showing loops of cord presenting above the internal cervical os. Flow confirmed with colour Doppler.

Cord presentation (also known as funic presentation) is a rare condition with a reported incidence ranging from 0.006% to 0.16% in third trimester scans, 1 and is defined as the presence of the umbilical cord between the fetal presenting part and the cervix, with or without intact membranes. 2 To the best of our knowledge, no studies have addressed detection of this condition during labour, therefore, incidence and optimal management are not established. The main concern regarding cord presentation relates to an increased risk of cord prolapse and associated perinatal morbi-mortality. 3

Suspicion may arise during vaginal examination but the diagnosis may not clear. Ultrasound can confirm the diagnosis by showing the presence of umbilical cord between the fetal presenting part and the cervix.

Spontaneous resolution by time of delivery can occur when the diagnosis is established during third trimester scan. However, the combination of ruptured membranes and cord presentation during labour precedes an inevitable cord prolapse, as cervical dilation progress. Therefore, we agree with the majority of authors recommending caesarean section when funic presentation is found during labour. 4

Learning points

Cord presentation is a rare condition during labour, associated with imminent risk of cord prolapse.
Diagnosis may be suspected during vaginal examination and is confirmed by ultrasound.
Caesarean section is recommended when diagnosis is established during labour.

Contributors: All authors were responsible for the diagnosis and management of the case reported. Dr TA was responsible for writing of the report. Dr JCG and Professor TR were responsible for the corrections before submission of the document.

Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests: None declared.

Provenance and peer review: Not commissioned; externally peer reviewed.

IMAGES

Labor and Birth Processes
Normal Labor
types of presentation in labour
types of presentation in labour
6. Nursing Care of Mother and Infant During Labor and Birth
Obsetrics 110 Fetal Presentation Presenting part position difference importance what is

COMMENTS

Fetal Presentation, Position, and Lie (Including Breech Presentation)
Fetal Presentation, Position, and Lie (Including Breech Presentation) - Learn about the causes, symptoms, diagnosis & treatment from the Merck Manuals - Medical Consumer Version.
Fetal presentation before birth
Fetal presentation before birth The way a baby is positioned in the uterus just before birth can have a big effect on labor and delivery. This positioning is called fetal presentation. Babies twist, stretch and tumble quite a bit during pregnancy.
Delivery, Face and Brow Presentation
The term presentation describes the leading part of the fetus or the anatomical structure closest to the maternal pelvic inlet during labor. The presentation can roughly be divided into the following classifications: cephalic, breech, shoulder, and compound. Cephalic presentation is the most common and can be further subclassified as vertex, sinciput, brow, face, and chin. The most common ...
Abnormal Fetal lie, Malpresentation and Malposition
The lie, presentation and position of a fetus are important during labour and delivery. In this article, we will look at the risk factors, examination and management of abnormal fetal lie, malpresentation and malposition.
Presentation and Mechanisms of Labor
The fetus undergoes a series of changes in position, attitude, and presentation during labor. This process is essential for the accomplishment of a vaginal delivery. The presence of a fetal malpresentation or an abnormality of the maternal pelvis can significantly impede the likelihood of a vaginal delivery. The contractile aspect of the uterus ...
Management of malposition and malpresentation in labour
A recap of normal fetal lie, presentation and position in labour The vast majority of fetuses at term will be in longitudinal lie, with a well flexed cephalic presentation in the occipito-anterior position just prior to delivery.
Face and Brow Presentation: Overview, Background, Mechanism of Labor
Nonvertex presentations (including breech, transverse lie, face, brow, and compound presentations) occur in less than 4% of fetuses at term. Malpresentation of the vertex presentation occurs if there is deflexion or extension of the fetal head leading to brow or face presentation, respectively.
Presentation and Mechanism of Labor
The mechanism of normal labor is series of events that take place in the genital organ that allow the birth of a viable fetus at term; followed by expulsion of placenta and membrane from the vagina. World Health Organization defines normal labor as starting spontaneously at term (37 completed weeks of gestation) for a fetus with cephalic ...
Malpresentations and Malpositions Information
Breech presentation is the most common malpresentation, with the majority discovered before labour. Breech presentation is much more common in premature labour. Approximately one third are diagnosed during labour when the fetus can be directly palpated through the cervix.
Face and brow presentations in labor
The vast majority of fetuses at term are in cephalic presentation. Approximately 5 percent of these fetuses are in a cephalic malpresentation, such as occiput posterior or transverse, face ( figure 1A-B ), or brow ( figure 2) [ 1 ]. Diagnosis and management of face and brow presentations will be reviewed here.
Mechanism of Labour
At the onset of labour, the position of the fetus with respect to the birth canal is crucial to the mechanism of labour and some important relationships include fetal lie, presentation, attitude and position (Table 1 ).
Compound fetal presentation
Compound presentation is a fetal presentation in which an extremity presents alongside the part of the fetus closest to the birth canal. The majority of compound presentations consist of a fetal hand or arm presenting with the head [ 1 ]. This topic will review the pathogenesis, clinical manifestations, diagnosis, and management of this ...
Presentation (obstetrics)
Presentation (obstetrics) In obstetrics, the presentation of a fetus about to be born specifies which anatomical part of the fetus is leading, that is, is closest to the pelvic inlet of the birth canal. According to the leading part, this is identified as a cephalic, breech, or shoulder presentation. A malpresentation is any presentation other ...
Breech presentation management: A critical review of leading clinical
Each of the clinical guidelines were reviewed in terms of recommended methods for fetal monitoring, maternal birth positions, clinicians, available facilities, pain relief, first and second stage, labour induction or augmentation and management of women who presented with an undiagnosed breech presentation in labour (see Table 4 ).
Face Presentation
The new paradigm is that babies match the space available. Face and brow presentations occur when baby's spine extended until the head is shifted back so baby's face comes through the pelvis first. Baby may settle in a face or brow presentation before labor or they may become a face or brow presentation, usually when a posterior baby has it ...
Stages of labor and birth: Baby, it's time!
Find out what happens during the different stages of labor and birth.
Management of Breech Presentation
Intrapartum assessment and management of women presenting unplanned with breech presentation in labour Where a woman presents with an unplanned vaginal breech labour, management should depend on the stage of labour, whether factors associated with increased complications are found, availability of appropriate clinical expertise and informed ...
Normal Labor and Delivery: Practice Essentials, Definition ...
Obstetricians have divided labor into 3 stages that delineate milestones in a continuous process. First stage of labor. Begins with regular uterine contractions and ends with complete cervical dilatation at 10 cm. Divided into a latent phase and an active phase. The latent phase begins with mild, irregular uterine contractions that soften and ...
Malpositions and malpresentations in Labour
The occipitoposterior (OP) position is the most common malposition. The fetus lies with its back against the mother's, the occiput in the posterior part of the pelvis with the head deflexed. Shoulder presentation is the most serious malpresentation in labour and constitutes an obstetric emergency.
Cord presentation in labour: imminent risk of cord prolapse
Cord presentation is a rare condition during labour, associated with imminent risk of cord prolapse. Diagnosis may be suspected during vaginal examination and is confirmed by ultrasound.

Fetal Presentation, Position, and Lie (Including Breech Presentation)

Position and Presentation of the Fetus

Variations in Fetal Position and Presentation

Occiput posterior position

Breech presentation

Other presentations

Abnormal Fetal lie, Malpresentation and Malposition

Definitions

Risk Factors

Identifying Fetal Lie, Presentation and Position

Presentation

Investigations

Abnormal Fetal Lie

Malpresentation

Malposition

Privacy Overview

INTRODUCTION

MECHANISM OF NORMAL LABOR

Maternal pelvis (passage)

Uterine activity (power)

Fetus (passenger)

Mechanism of normal labor

PRACTICE RECOMMENDATIONS

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Managing conditions

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Malpresentations and malpositions

In this article :

Obstetrics - the pelvis and head

Breech presentation

Transverse lie 4

Occipito-posterior position

Occipito-transverse position

Face presentations

Brow positions

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Article history

Next review due: 21 Jun 2026

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Mechanism of Labour

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Stages of labor and birth: Baby, it's time!

Stage 1: Early labor and active labor

Cervical effacement and dilation

Early labor

Active labor

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Stage 3: Delivery of the placenta

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Normal Labor and Delivery

Stages of labor

First stage of labor

Second stage of labor

Third stage of labor

Mechanism of labor