Question 20

A 37 yo primigravida undergoes IOL at 39 weeks. After 4 hours of second stage, she has a forceps-assisted vaginal delivery of a male infant weighing 4200g. Delivery is complicated by a shoulder dystocia and neonatal humerus fracture. Delivery ultimately occurred after lateral traction of the fetal head, McRoberts maneuver, suprapubic pressure, rotation of the fetal shoulders and delivery of the posterior arm. After delivery, the newborn is diagnosed with a brachial plexus injury. In this patient, the action that has been shown to increase infant brachial plexus stretching is:

Answer Choices:

Delivery of the posterior arm

Forceps-assisted vaginal delivery

Lateral traction of the fetal head

Rotation of the fetal shoulders

Correct Answer:

Lateral traction of the fetal head

Explanation:

  • Shoulder dystocia is defined by a delivery where the gentle downward traction of the fetal head fails to result in delivery of the fetal shoulders

  • Most cases resolve without neonatal injury.

  • Brachial plexus injury occurs in 1.5 of 1000 deliveries. Involves a weak or paralyzed upper extremity involving either the upper cervical nerve roots (Erb palsy) or lower cervical nerve roots (Klumpke palsy)

  • The majority of cases of brachial plexus injury resolve spontaneously

  • Downward lateral traction on the fetal head (when fetal neck is bent away from the anterior shoulder) results in significant increase in extraction forces and brachial plexus stretching

  • The preferred traction is axial (forces are in parallel to the fetal cervicothoracic spine) and no more than 25-45 degrees below the horizontal plane when the patient is in lithotomy position.