Induction of labor or serial antenatal fetal monitoring in postterm pregnancy: a randomized controlled trial

Abstract

Objective: To compare induction of labor at gestational age 41 weeks with expectant management in regard to neonatal morbidity. Secondary aims were to assess the effect of these managements on mode of delivery and maternal complications.

Methods: Between September 2002 and July 2004, postterm women with singleton cephalic presentation and no prelabor rupture of membranes were randomly assigned to induction of labor at 289 days or antenatal fetal surveillance every third day until spontaneous labor. Main outcome measures were neonatal morbidity, operative delivery rates, and maternal complications.

Results: Five hundred eight women were randomly assigned, 254 in each group. No differences of clinical importance were observed in women in whom labor was induced compared with women who were expectantly managed with regard to the following outcomes: neonates whose 5-minute Apgar score was less than 7 (three neonates in the induction group compared with four in the monitoring group, P=.72); neonates whose umbilical cord pH was less than 7 (three compared with two, P=.69); prevalence of cesarean delivery (28 compared with 33, P=.50); or prevalence of operative vaginal delivery (32 compared with 27, P=.49). In the induction group more women had precipitate labors (33 compared with 12, P<.01; number needed to treat was 13), and the duration of second stage of labor was more often less than 15 minutes (94 compared with 56, P<.01; number needed to treat was 7).

Conclusion: No differences were found between the induced and monitored groups regarding neonatal morbidity or mode of delivery, and the outcomes were generally good.

Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00385229.

Level of evidence: I.