Shoulder dystocia is defined as failure to deliver the fetal shoulders following delivery of the head. Dystocia is caused by impaction of the fetal shoulders against the pelvic outlet. Often, it is diagnosed by retraction of the fetal head against the perineum after delivery (“turtle sign”). Risk factors include gestational diabetes, prior shoulder dystocia or delivery of large infants, and postterm delivery.
Management and Disposition
Shoulder dystocia is an acute obstetric emergency due to the immediate threat of fetal asphyxia from compression of umbilical cord and chest. Immediate obstetric and pediatric consultation is imperative. Prepare equipment for delivery, possible episiotomy, and neonatal resuscitation. Upon identification of a shoulder dystocia, attempt McRobert maneuver (the least invasive procedure). This maneuver involves flexing the mother’s knees toward and past her chest in an extreme dorsal lithotomy position while simultaneously applying firm suprapubic pressure in an attempt to disengage the infant’s shoulder from the pelvic rim. Do not apply fundic pressure as this may worsen the fetal lodging against the pubic bone. If McRobert maneuver is unsuccessful, a Woods screw maneuver can be attempted by hooking two fingers behind the infant’s posterior scapula and rotating the entire body. As the anterior shoulder rotates downward, it can generally be delivered past the symphysis pubis. If the Woods maneuver fails to deliver the anterior shoulder, delivery of the posterior arm may be attempted by inserting two fingers into the sacral fossa and delivering the entire posterior arm by flexing it at the elbow. The remaining shoulder should then deliver spontaneously or following rotation into the oblique position to facilitate its delivery. In extreme cases, emergency cesarean may be necessary.
Shoulder dystocia is an acute obstetric emergency that requires quick action.
After delivery, look for fractures of the infant’s clavicle or humerus and evidence of a brachial plexus injury. Damage to the 5th and 6th cervical nerve roots with resultant Erb palsy is the most common injury.
Shoulder Dystocia. Firm approximation of the fetal head against the vaginal outlet consistent with shoulder dystocia. (Photo contributor: William Leininger, MD.)