Postterm with favorable cervix: is induction necessary?

Objective: To study the cesarean rate between expectant management and immediate induction in the otherwise uncomplicated postterm pregnancy with favorable cervix.

Study Design: A total of 249 women with uncomplicated pregnancies at 41 weeks plus 3 days (290 days) with favorable cervix (Bishop score > or =6) were randomized to either expectant management (n=125) or immediate induction of labor (n=124). The women in the induction group were sent to labor ward for induction by artificial rupture of membranes (ARM) and/or oxytocin infusion. The women with expectant management had nonstress test (NST) and amniotic fluid index (AFI) performed once a week and twice a week after 43 weeks of gestation until spontaneous labor.

Results: The cesarean rate was not different between expectant management and immediate induction (21.6% versus 26.6%; P=0.36). Ninety-five percent of the expectant group delivered within 1 week after enrollment, and all of them delivered within 9 days after randomization. Maternal and fetal complications in both groups were not different. There was also no difference in the mean birth weight (P=0.24) and the frequency of macrosomia (birth weight > or = 4000 g) between the two groups (P=0.23).

Conclusion: Cesarean section rate between expectant management and immediate induction in the otherwise uncomplicated postterm pregnancy with favorable cervix was not different. Due to the very low adverse perinatal outcome, both expectant management and immediate induction are acceptable.