Review Question - QID 106912

This delivery has been complicated by impaction of the shoulder and possible shoulder dystocia (SD). Several possible interventions can be used to address this condition, including delivery of the POSTERIOR, not anterior, arm.

SD is caused by impaction of the anterior shoulder of the fetus on the pubic symphysis of the mother. Maternal obesity, gestational diabetes, fetal macrosomia, and prolonged second stage of labor are all risk factors for SD. The "turtle sign" is the classical sign associated with SD, in which the fetal head retracts back into the introitus during delivery. Treatment includes non-manipulative maneuvers, such as suprapubic pressure or flexion of the maternal hips, as well as manipulative maneuvers, such as delivery of the posterior arm and rotation of the shoulders 180 degrees. Pushing the fetal head back into the vaginal canal and resorting to an emergent C-section is also possible (Zavanelli maneuver).

Baxley and Gobbo discuss the management of shoulder dystocia. They note that one of the major complications is compression of the umbilical cord between the fetal body and the maternal pubic symphysis, which can lead to fetal hypoxia. In cases that don't respond to first-line maneuvers, physicians can consider performing a clavicle fracture, symphysiotomy, or the Zavanelli maneuver.

Sirota et al. perform a retrospective study comparing the incidence of shoulder dystocia in obese mothers with spontaneous versus induced deliveries. They found that deliveries that were induced or augmented resulted in a higher incidence of shoulder dystocia.

Illustration A shows the anatomic challenge presented by SD. Shoulder dystocia causes pulling of the neck away from the anterior shoulder, which can lead to a brachial plexus injury. Typically, the tension causes damage to the upper trunk of the brachial plexus, leading to an Erb-Duchenne Palsy.

Incorrect Answers:
Answers 1-3, 5: These maneuvers can all be used as treatment for SD.