What is the most appropriate next step in managing shoulder dystocia after delivery of the head?

Management of Shoulder Dystocia in Obstetric Emergency

The most appropriate next step in managing shoulder dystocia after delivery of the head is to perform the McRoberts maneuver by flexing the woman's knees toward her shoulders. 1

Initial Management Algorithm

When shoulder dystocia is recognized after delivery of the head:

1. Announce the emergency: Clearly state "shoulder dystocia" to alert the team
2. Call for additional help: Summon extra assistance immediately
3. Perform McRoberts maneuver:
   • Position the mother with her legs hyperflexed tightly to her abdomen 1
   • This maneuver flattens the sacrum relative to the lumbar spine and rotates the symphysis pubis toward the maternal head
   • No forceful traction should be applied to the fetal head during this maneuver 2

Evidence for McRoberts as First-Line Intervention

The 2022 guidelines for management of urgent obstetric situations explicitly state that "in the event of proven shoulder dystocia, the McRoberts maneuver is recommended, whether associated or not with suprapubic pressure, as first-line intervention" 1. This recommendation carries strong expert agreement and is designed to reduce maternal and fetal morbidity and mortality.

McRoberts maneuver works by:

• Straightening the sacrum relative to the lumbar spine
• Rotating the symphysis pubis
• Decreasing the angle of pelvic inclination
• Facilitating disimpaction of the anterior shoulder

Second-Line Interventions

If McRoberts maneuver fails to resolve the dystocia, proceed to:

1. Suprapubic pressure (not fundal pressure) 1, 3
2. Delivery of the posterior arm 4
   • This is particularly effective when the posterior shoulder is engaged 4
   • Success rates are higher than continued attempts with McRoberts alone

The success rate of McRoberts with or without suprapubic pressure is approximately 25.8% overall 3, but varies significantly based on delivery circumstances:

• 47.7% success after spontaneous vaginal delivery
• Only 15.0% success after instrumental delivery 3

Important Cautions

1. Avoid excessive traction on the fetal head as this increases risk of brachial plexus injury 4, 2
2. Do not perform fundal pressure as this can worsen the impaction 4
3. Do not attempt to rotate the fetal head 180 degrees as the initial maneuver, as this can cause cervical spine injury 4
4. Track the time from delivery of the head to complete delivery of the neonate 5

When First-Line Measures Fail

If McRoberts maneuver with suprapubic pressure fails, proceed systematically:

1. Deliver the posterior arm (Jacquemier's maneuver) - especially effective when the posterior shoulder is not engaged 4
2. Internal rotational maneuvers (Wood's screw or Rubin's maneuver) - particularly when the posterior shoulder is engaged 4
3. Consider shoulder shrug technique in persistent cases - involves shrugging the posterior shoulder and rotating the head-shoulder unit 6

The evidence suggests that no second-line maneuver is clearly superior to others, and the choice should be based on the specific clinical situation and operator experience 4.

Remember that calm, methodical application of these techniques in the correct sequence will resolve most cases of shoulder dystocia while minimizing trauma to both mother and infant.