Vaginal delivery of vertex-nonvertex twins: a fading skill?

Delivery of the second twin is one of the most challenging events for practicing obstetricians. Due to the increased incidence of twin gestations and lack of well-designed clinical trials, evidence-based recommendations are lagging behind clinical demand. The present review examines the practice of second nonvertex twin deliveries. A review of the literature was conducted using the term vertex-nonvertex; twin gestation; mode of delivery; and cesarean delivery. There is a lack of evidence supporting the appropriate approach to second nonvertex twin deliveries. Larger studies with increased power are needed to examine the variations regarding gestational period, birth weight, and institutional experience. In the mean time, unless otherwise contraindicated, it is reasonable to attempt vaginal delivery and total breech extraction and proceed to assisted delivery or cesarean delivery if unsuccessful. Preserving the art of obstetric maneuvering is important as well for twin deliveries. In cases of vertex-nonvertex presentation, vaginal delivery is preferred in certain conditions.