Breech deliveries and cesarean section.

Breech presentation is the most common malpresentation, with about 3-4% of singleton fetuses presenting breech at delivery. Management of breech presentation has been a contentious issue with a lowering threshold for cesarean section in recent years. Perinatal mortality and morbidity are estimated to be three times that of comparable infants with vertex presentation. Breech presentation is commonly associated with certain adverse maternal and fetal factors which inherently give rise to increased perinatal morbidity and mortality. At present, most obstetricians favor cesarean delivery for uncomplicated pre-term breech. Controlled prospective studies have shown that the outcome of breech fetuses weighing more than 1500 g was not dependent on the mode of delivery. A more recent review from the Cochrane database by Grant does not justify a policy of elective cesarean section for pre-term breech. Vaginal delivery is preferred if the following criteria are met: frank breech only, estimated fetal weight of 2500-3500 g, adequate pelvimetry without hyperextended head, normal progression of labor, no evidence of fetal hypoxia under continuous fetal monitoring, and maternal weight under 90 kg. Vaginal delivery of frank breech at term may be just as safe as cesarean section when careful selection criteria are used. If these criteria are not fulfilled, or fetal monitoring cannot be performed, cesarean section is advisable.