Refers to a situation where, after delivery of the head, the anterior shoulder of the fetus becomes impacted on the maternal pubic symphysis, or (less commonly) the posterior shoulder becomes impacted on the sacral promontory

Aetiology

Risk factors

• Antenatal:
  • Previous shoulder dystocia
  • Obesity (BMI >30)
  • Short stature
  • Diabetes
  • Fetal acrosomia
• Intrapartum:
  • Prolonged 1st and 2nd stage
  • Induction of labour
  • Instrumental delivery

Clinical features

• Defined by a delay in delivery of the shoulders following the head during a vaginal delivery with the next contraction after using normal traction
• On examination, signs that may occur to aid the diagnosis are:
  • Slow delivery of the head, face and chin
  • Failure of restitution - the foetal remains in the occipital-anterior position after delivery by extension and therefore does not ‘turn to look to the side’
  • ‘Turtle neck’ sign - the foetal head retracts slightly back into the pelvis, so that the neck is no longer visible, akin to a turtle retreated into its shell
  • 'Head bobbing' - this is when the head consistently retracts back between contractions during the active second stage

Management - HELPERR

• Call for Help
• Evaluate for episiotomy
• Legs (McRoberts' manoeuvre)
• External Pressure (suprapubic)
• Enter (rotational manoeuvre)
• Remove the posterior arm
• Roll the patient onto her hands and knees

Complications

Fetal

• Hypoxia
• Brachial plexus injury