Obstetric emergency where the foetal shoulder is impacted behind the maternal pubic symphysis or sacral promontory.
Manifests as difficulty delivering the shoulders after the head, often with the turtle sign.
McRoberts manoeuvre is the first-line intervention.
Can lead to brachial plexus injury, perineal tears, or neonatal hypoxia.
🧬 Pathophysiology
The anterior shoulder (more commonly) or posterior shoulder becomes lodged behind the maternal bony pelvis after delivery of the foetal head.
Requires additional manoeuvres to complete delivery.
Can lead to cord compression and hypoxia if not managed promptly.
Figure 207: Shoulder dystocia - Note the anterior shoulder impacting on the maternal pubic symphysis. Henry Lerner. Suprapubic-pressureforSD, CC BY 4.0
⚠️ Risk Factors
Foetal macrosomia
Maternal diabetes
Maternal obesity
Prolonged second stage of labour
Previous shoulder dystocia
Instrumental delivery (e.g. forceps, vacuum)
👀 Clinical Features
Difficulty delivering shoulders after the head.
Turtle sign: retraction of foetal head against the perineum after delivery.
Failure of gentle traction alone to achieve delivery.
💊 Management
Call for immediate help and initiate manoeuvres:
1st line: McRoberts manoeuvre: hyperflex maternal hips onto the abdomen to rotate the symphysis and flatten the sacrum.
RCOG: “McRobert’s is a simple, rapid and effective intervention and should be performed first”
Suprapubic pressure: apply continuous or rocking pressure just above the pubic bone.
Rubin manoeuvre: apply pressure on the posterior aspect of the anterior shoulder to rotate it.
Wood’s screw manoeuvre: rotate posterior shoulder using internal pressure to release anterior shoulder.
Delivery of posterior arm: gently bring out posterior arm to reduce bisacromial diameter.
Gaskin manoeuvre: move mother to all fours position.
Consider episiotomy if internal manoeuvres are difficult.
🛡️ Prevention
Optimise diabetes control in pregnancy.
Consider elective caesarean if high risk (e.g. macrosomia with diabetes, previous shoulder dystocia).
⚠️ Complications
Foetal
Brachial plexus injury (Erb's palsy)
Fractures (clavicle or humerus)
Hypoxic-ischaemic injury or neonatal death
Maternal
Postpartum haemorrhage
Perineal tears (including third/fourth degree)
Uterine rupture (rare)
📝 Exam Clues & Clinchers
Turtle sign after head delivery → shoulder dystocia.
First step is always McRoberts + suprapubic pressure.
