Influence of spontaneous or induced labor on delivering the macrosomic fetus.

Fetal macrosomia is a known intrapartum risk factor for fetal injury and maternal morbidity. The purpose of this study was to review our experience with macrosomic fetuses in nondiabetic pregnancies and compare perinatal outcomes between those whose labor had been spontaneous or induced. Between January 1989 and December 1991, the 186 pregnancies of infants with birthweights greater than 4000 g (4001 to 5131 g) underwent labor that had been induced (46) or spontaneous (140). Cesarean delivery was more common after induced than spontaneous labor (11 [23.9%] vs 14 [10.0%]; P < 0.03) regardless of parity or gestational age. Frequencies of shoulder dystocia, 1-minute Apgar scores less than 7, and abnormal umbilical blood gas determinations were not different between the two groups. We conclude that spontaneous rather than induced labor is associated with a lower chance of cesarean delivery among those fetuses with birthweights 4000 g or more.