Editor-In-Chief: C. Michael Gibson, M.S., M.D. 
Shoulder dystocia is a specific case of dystocia whereby the anterior shoulder of the infant cannot pass below the pubic symphysis, or requires significant manipulation to pass below, the pubic symphysis. It is diagnosed when the shoulders fail to deliver shortly after the fetal head.
A number of obstetrical maneuvers are used to facilitate delivery at this point, including McRobert's maneuver; suprapubic pressure (or Rubin I); Rubin II or posterior pressure on the anterior shoulder; Woods' screw maneuver which leads to turning the anterior shoulder to the posterior and vice versa; and Jacquemier's maneuver (also called Barnum's maneuver), or delivery of the posterior shoulder. More drastic maneuvers include Zavanelli's maneuver or internal cephalic replacement followed by Cesarean section; intentional clavicular fracture, symphisiotomy, and abdominal rescue, described by O'Shaughnessy, where a hysterotomy facilitates vaginal delivery of the impacted shoulder.
Although the definition is imprecise, it occurs in approximately 1% of vaginal births. There are well-recognised risk factors, such as diabetes, fetal macrosomia, and maternal obesity, but it is often difficult to predict. Despite appropriate obstetric management, fetal injury (such as brachial plexus injury) or even fetal death can be a complication of this obstetric emergency.