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Shoulder Dystocia

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Shoulder dystocia\: a complication of vaginal cephalic delivery where the anterior fetal shoulder becomes stuck on the
maternal pubic symphysis, delaying the birth of the baby’s body.
Obstetric emergency\: occurs in about 1 in 150 vaginal births; risk of hypoxic brain injury if delivery is delayed.
Pathophysiology\: baby’s head is delivered, but shoulders prevent further progression; compression of the umbilical cord or
baby’s neck limits blood
Risk factors\: previous shoulder dystocia, macrosomia >4.5kg, diabetes mellitus, maternal BMI >30, induction of labour,
prolonged
Clinical features\: slower delivery of the head, inability to deliver the anterior shoulder after head delivery, turtleneck sign
(appearance and retraction of the baby’s head).
Investigations\: no immediate investigations; focus on urgent intervention; post-delivery assessment for shock and
haemorrhage (vital signs, full blood count, crossmatch and group and save).
Initial management\: call for help, advise the mother to stop pushing, McRoberts manoeuvres (hyper
apply suprapubic pressure), posterior arm delivery, internal rotation, and avoid downward traction on the fetal head.
Post-delivery management\: active management of the third stage of labour, support and debrief the mother, rectal
examination to exclude third-/fourth-degree tears, paediatric review for complications (e.g. brachial plexus injury).
Future deliveries\: inform of the risk of recurrence and provide options for subsequent deliveries.
Complications\: maternal (third-/fourth-degree tears, postpartum haemorrhage, trauma/PTSD); fetal (brachial plexus injury,
fractures of the humerus or clavicle, hypoxic brain injury).
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Introduction

Shoulder dystocia is a complication of vaginal cephalic delivery when the anterior fetal shoulder becomes stuck on the
maternal pubic symphysis resulting in delayed birth of the baby’s body.
Shoulder dystocia is an obstetric emergency and occurs in about one in 150 vaginal births. If there is a delay to delivery,
there is a risk of hypoxic brain injury for the baby.

Aetiology

Shoulder dystocia usually occurs unexpectedly during childbirth and is not predictable.

Pathophysiology

When shoulder dystocia occurs the baby’s head is delivered but the shoulders prevent progression. This happens
because the shoulders, at the point of the head being delivered, are only just reaching the pelvic
still negotiating the pelvic outlet (see the Geeky Medics article on the mechanism of labour).
The shoulder compression may cause the umbilical cord to become compressed between the baby’s body and the
mother’s pelvis or the baby’s neck may be compressed at an angle that limits blood
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Interruption of the oxygen supply may cause hypoxic brain injury potentially resulting in permanent functional change.
The longer the baby is trapped, the greater the risk of hypoxic injury. However, the overall incidence of brain injury remains
low in shoulder dystocia as prompt management improves outcomes.

Risk factors

Pre-labour risk factors for shoulder dystocia include\:
1
Previous shoulder dystocia
Macrosomia >4.5kg
Diabetes mellitus
Maternal body mass index >30
Induction of labour
Intrapartum risk factors for shoulder dystocia include\:
Prolonged
Secondary arrest\: no change in cervical dilation over time.
Prolonged second stage of labour
Oxytocin augmentation
Assisted vaginal delivery
Shoulder dystocia is more likely in babies with higher birth weights, but it should be noted that there is no di
delivering the shoulders in most babies over 4.5kg.
If a woman has diabetes the risk is signi
or develops diabetes in pregnancy, they will usually be o
reduce/eliminate the risk of shoulder dystocia.

Clinical features

History

this diagnosis.
Shoulder dystocia is an obstetric emergency often with no features or warning signs therefore history is less relevant to

Clinical examination

Typical clinical
Slower delivery of the head
Unable to deliver the anterior shoulder after the delivery of the head with the next contraction
Turtleneck sign\: the appearance and retraction of the baby's head (like a turtle withdrawing into its shell), with a red,
pu

Di

Possible di
Congenital abnormality preventing easy delivery of the baby

Investigations

There are no immediate relevant investigations as shoulder dystocia is a time-critical obstetric emergency requiring
urgent intervention.
Following delivery, assessment and investigations for shock and haemorrhage need to be performed quickly.
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Bedside investigations

Relevant bedside investigations include\:
Vital signs\: monitoring for shock

Laboratory investigations

Relevant laboratory investigations include\:
Full blood count
Crossmatch and group and save\: possibility of post-partum haemorrhage as a complication

Management

Initial management

Initial management of shoulder dystocia includes\:
Call for help\: obstetric emergency (senior obstetrician, senior midwife and paediatrician will need to be present)
Advise the mother to stop pushing\: can worsen the fetal impaction.
McRoberts manoeuvres (
a success rate of about 90% which is even higher when combined with suprapubic pressure. Suprapubic pressure is
pressure applied behind the anterior shoulder to disimpact it from the maternal symphysis (Figure 1 number 2).
Figure 1. McRoberts (1) with suprapubic
pressure (2).
2
If
Posterior arm\: inserting the hand posteriorly to grasp the posterior fetal arm and deliver
Internal rotation (‘corkscrew’)\: simultaneously applying pressure in front of one shoulder and behind the other. The aim
is to rotate the baby 180 degrees.
An episiotomy can allow more space to facilitate internal vaginal manoeuvres but will not relieve the bony obstruction of
the shoulder. The use of an episiotomy will not decrease the risk of brachial plexus injury.
Always avoid downwards traction on the fetal head as this increases the risk of brachial plexus injury.

Post-delivery management

Post-delivery management includes\:
Active management of the third stage of labour is recommended due to the increased risk of post-partum haemorrhage
Shoulder dystocia can be a traumatic experience for the mother and birth partner, provide support and debrief the
following delivery
A rectal examination should be performed to exclude a third- or fourth-degree tear
Paediatric review is recommended before discharge to assess for complications such as brachial plexus injury

Future deliveries

There is a risk of recurrence with any subsequent deliveries. Mothers should be informed of this risk and given options for
subsequent deliveries.

Complications

The complications of shoulder dystocia can be divided into maternal and fetal.
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Maternal complications of shoulder dystocia include\:
Third- or fourth-degree tears
Post-partum haemorrhage
Trauma/post-traumatic stress disorder
Foetal complications of shoulder dystocia include\:
Brachial plexus injury (BPI)
Fractures\: humerus or clavicle
Hypoxic brain injury.
Brachial plexus injury
Approximately one in ten babies who have shoulder dystocia will have a degree of stretching of the brachial nerve
plexus in the neck, called brachial plexus injury.
The most common type of BPI is called Erb’s palsy (Figure 3). It is usually temporary, and movement will return
within hours or days. Permanent damage is rare.
If managed appropriately the risk of permanent brachial plexus injury can be almost eliminated. However, it is
important to remember that BPI can occur without shoulder dystocia. BPI can also occur in babies born by caesarean
section.
Figure 2. Brachial plexus injury.
3
Figure 3. Erb’s palsy.
4
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References

RCOG. S h o u l d e r D y s t o c i a G r e e n- T o p G u i d e l i n e N o .4 2 E d i t i o n . Published in March 2012. Available from\: [LINK]
Geraldbaeck. M c R o b e r t s M a n o e u v r e . Licence\: [Public domain]
Donthatemebro. B r a c h i a l P l e x u s I n j u r y . Licence\: [CC BY-SA 3.0]
R. E r b s P a l s y . Licence\: [CC BY-SA 4.0]

Reviewer

Dr Rachel Greenwood
Obstetrics & Gynaecology Registrar

Related notes

Amniotic Fluid Embolism
Antenatal Screening for Down’s Syndrome
Antepartum Haemorrhage (APH)
Breech Presentation
Caesarean Section

Test yourself

Contents

Introduction
Aetiology
Risk factors
Clinical features
Di
Investigations
Management
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