Tell me about shoulder dystocia?

OB difficluty: Shoulder dystocia occurs when the baby descending into the pelvis "fails" to rotate under the pubic arch of the mother and the clavicle wedges against the pubic bone. There are OB manuevers to"unstick" the child for vaginal delivery, but the danger is that the fetal head may already be outside the mother and trying to "breathe". Cesarean sections are common.

Serious complication: Shoulder dystocia occurs when the baby's head delivers but the shoulders are too big to come through. This results in injury to the chest outlet (fracture of the clavicle), arm (fracture of the humerus) and/or the nerves traveling from the neck to the arm. Some of the nerve injuries are permanent and result in congenital arm paralysis. This dire complication occurs in large babies and/ big mothers.