Shoulder dystocia.

Shoulder dystocia continues to represent a largely unpredictable and potentially disastrous obstetric emergency. Recent attention has been focused on the effectiveness of obstetric maneuvers employed to alleviate shoulder dystocia. Reports have also questioned the traditional thinking that brachial plexus injury is caused by application of excessive lateral traction to the fetal head. Rather, in-utero forces may underlie a significant portion of these injuries.