Monochorionic monoamnionic twins: vaginal delivery.

Monochorionic monoamnionic pregnancies are rare and have a poor obstetric prognosis. A single amniotic sac promotes cord knotting and entanglement with a high risk of fetal anoxia. The response to this risk has been obstetric management consisting of routine cesarean section at 32 weeks of gestation or when pulmonary maturity is attained. This approach is called into question by the series of seven monochorionic monoamnionic pregnancies we present here. Such pregnancies do indeed require increased surveillance to term, but we think it is possible to apply the usual obstetric management of twin pregnancies.