What is shoulder dystocia and how is it managed?

Shoulder Dystocia Management

Shoulder dystocia is an obstetric emergency where normal traction on the fetal head does not lead to delivery of the shoulders, requiring additional maneuvers for successful delivery. 1 It requires immediate recognition and a structured approach to management to prevent serious complications.

Definition and Recognition

• Shoulder dystocia occurs when the anterior shoulder of the fetus becomes impacted against the maternal pubic symphysis after delivery of the head
• Diagnosis is made when "the obstetrician is unable to deliver the fetal head with their usual delivering hand, and additional maneuvers and/or tocolysis are required to disimpact and deliver the head" 2
• It is an unpredictable obstetric emergency that requires immediate action

Risk Factors

While most cases occur without warning, certain factors increase risk:

• Fetal macrosomia
• Prior shoulder dystocia
• Preexisting or gestational diabetes mellitus
• Maternal obesity
• Post-term pregnancy 1

Important note: Shoulder dystocia can occur in infants of normal birth weight, not just those with macrosomia 1

Prevention Considerations

• Current evidence does not support early induction of labor for suspected fetal macrosomia 1
• Prophylactic cesarean delivery may be considered for:
  • Estimated fetal weights >5,000g in non-diabetic women
  • Estimated fetal weights >4,500g in diabetic women 1
• Vaginal delivery is not contraindicated for estimated fetal weights up to 5,000g in non-diabetic women 1

Management Algorithm

When shoulder dystocia is recognized:

1. Announce the emergency clearly and call for additional help 1

2. Implement McRoberts maneuver as first-line intervention

   • Hyperflexion of mother's legs tightly to her abdomen 1
   • This flattens the sacral promontory and rotates the pubic symphysis

3. If McRoberts fails, proceed to suprapubic pressure (NOT fundal pressure) 1

4. If still unsuccessful, proceed to advanced maneuvers:

   • Delivery of the posterior arm
   • Internal rotational maneuvers (Woods' screw or Rubin's maneuver)
   • Gaskin maneuver (all-fours position) 3

5. Last resort maneuvers (rarely needed):

   • Intentional clavicular fracture
   • Cephalic replacement (Zavanelli maneuver) followed by emergency cesarean section 3, 4

Critical Points in Management

• Avoid excessive traction on the fetal head - can cause brachial plexus injury
• Never apply fundal pressure - can worsen impaction
• Do not attempt to rotate the fetal head 180 degrees - can cause cervical spine injury 1
• Keep track of time from delivery of the head to full delivery 3
• Maintain clear communication with the patient and healthcare team throughout

Potential Complications

Maternal:

• Trauma to the bladder, anal sphincter, and rectum
• Postpartum hemorrhage 3

Neonatal:

• Brachial plexus injuries
• Hypoxia
• Clavicular fractures (occur approximately 10 times more frequently in macrosomic infants) 1, 3

Training and Preparation

• The American College of Obstetricians and Gynecologists strongly recommends simulation-based training for managing shoulder dystocia 1
• Training should be multiprofessional and use validated, high-fidelity birth simulators
• Simulation should include practice of all disimpaction techniques and management algorithms 1
• Each institution should practice emergency protocols, including preparation time for operating room and general anesthesia if needed 3

Documentation

Thorough documentation is essential following a shoulder dystocia event:

• Time of delivery of head and complete delivery
• Maneuvers used and their sequence
• Personnel present
• Neonatal condition at delivery
• Any complications noted

Proper management of shoulder dystocia requires preparation, quick recognition, and a systematic approach to disimpaction maneuvers. With appropriate training and prompt intervention, most cases can be successfully managed with minimal maternal and neonatal morbidity.