Objective: Our purpose was to assess whether a program of expectant management of uncomplicated pregnancies in mothers with insulin-requiring gestational or pregestational class B reduces the incidence of cesarean birth.
Study design: Two hundred women with uncomplicated, insulin-requiring diabetes at 38 weeks' gestation who were compliant with care and whose infants were judged appropriate for gestational age were randomly assigned to (1) active induction of labor within 5 days or (2) expectant management. The expectant management group was monitored with weekly physical examination and twice-weekly nonstress tests and amniotic fluid volume estimation until delivery.
Results: Expectant management increased the gestational age at delivery by 1 week. Approximately half (49%) of the mothers in the expectant management group required induction of labor for obstetric indications. The cesarean delivery rate was not significantly different in the expectant management group (31%) from the active induction group (25%). The mean birth weight (3672 +/- 407 gm) and percentage large for gestational age, as defined by birth weight > or = 90th percentile, of infants in the expectantly managed group (23%) was greater than those in the active induction group (3466 +/- 372 gm, p < 0.0001, 10% large for gestational age). This difference persisted after controlling for gestational age and maternal age and body weight (p < 0.01).
Conclusion: In women with uncomplicated insulin-requiring gestational or class B pregestational diabetes, expectant management of pregnancy after 38 weeks' gestation did not reduce the incidence of cesarean delivery. Moreover, there was an increased prevalence of large-for-gestational-age infants (23% vs 10%) and shoulder dystocia (3% vs 0%). Because of these risks, delivery should be contemplated at 38 weeks and, if not pursued, careful monitoring of fetal growth must be performed.