To assess the impact of transverse lie on fetal and neonatal outcome, 14 mother and infant pairs with transverse lie were matched to 28 pairs with a vertex and 28 with a breech presentation. The control groups were matched for gestational age, route of delivery, type of anesthesia, and presence of labor. Infants in transverse lie were found to have a lower absolute arterial pH (7.21 versus 7.27, p less than 0.05) as well as more frequent severe acidosis (pH less than 7.1, 3 of 14 versus 0 of 56, p less than 0.04). Their birthweight was also less (2798 gm versus 3251 gm, p less than 0.05) and they sustained more birth trauma and long-term residual effects than either the breech (5 of 14 versus 1 of 28, p = 0.01) or vertex control groups (5 of 14 versus 2 of 28, p = 0.03). Based on these results, we recommend active intervention at 38 weeks' gestational age, via external version followed by labor induction, or failing this, cesarean delivery.