Shoulder dystocia.

Shoulder dystocia is an infrequent and unexpected emergency requiring rapid and deft solution. Identifiable risk factors include maternal diabetes, fetal macrosomia (especially in the presence of diabetes), and maternal history of previous delivery of a large infant. Other reported risk factors include arrest and protraction disorders of labor and midpelvic operative delivery; however, more than 50% of shoulder dystocia occurs in instances without identifiable risk factors, and permanent neonatal injury is thus unpredictable. Therefore, all personnel in the delivery suite must be well versed in the timely and appropriate application of corrective measures. Although most instances of shoulder dystocia cannot be predicted, the judicious use of CS delivery in diabetic patients with expected birth weights of more than 4250 g should reduce the risk of shoulder dystocia in this subgroup of patients. A trial of labor for nondiabetic patients with suspected fetal macrosomia is recommended because predicting actual birth weights in this population remains difficult.