• Obstetrics & Gynecology Clinical Trials
• Pregnancy
• Diagnostic & Surgical Procedures

• Obstetrics & Gynecology
• Obstetrics & Gynecology Clinical Trials
• Pregnancy
• Diagnostic & Surgical Procedures

Elective induction of labor (IOL) is not uncommon at 39 weeks' gestation, but prospective data on perinatal outcomes and ultimate mode of delivery are limited compared to expectant management (EM). The Elective Induction of Nulliparous Labor study [Miller NR et al. Obstet Gynecol 2014; NCT01076062] was presented by Nathaniel Miller, MD, Carl R. Darnall Army Medical Center, Fort Hood, Texas, USA. The researchers' objectives were to evaluate the incidence of cesarean delivery and perinatal outcomes among women who deliver by elective IOL compared with spontaneous labor.

A total of 8899 pregnant women were screened between March 2010 and February 2014. Nulliparous women, aged 18 to 40 years, with an uncomplicated pregnancy and a Bishop score ≤5 receiving care at a single medical center who met the inclusion criteria and consented to randomization were randomized to IOL at 39 weeks (n=82) versus EM (n=80). Exclusion criteria included multiparity, <38.0 or >38+6 weeks estimated gestational age (EGA); nonvertex presenting; contraindications to labor; multiple gestation; and current medical indication for IOL. The women randomly assigned to EM received standard of care, including routine clinic appointments until delivery, and nonstress testing during their 41st week if they had not delivered by then. Women in the EM group who did not go into labor by 42 weeks were scheduled for IOL. The a priori power analysis assumed a cesarean delivery rate of 20% in the control/EM group, and was designed using a p of 0.05 and a power of 0.8 to detect a 2-fold increase in the cesarean delivery rate in the IOL group.

Baseline analysis found a significantly higher body mass index in the IOL group (32.2±4.5 kg/m²) versus the EM group (30.2±4.1 kg/m²; p=0.03) and a higher Bishop score at admission in the EM group (7.7±2.7) versus the IOL group (5.2±2.4; p<0.01).

Analysis found an increased trend but no statistically significant difference in cesarean deliveries when comparing the IOL group (30%, n=25) with the EM group (18%, n=14; relative risk, 1.7; 95% CI, 0.97 to 3.06; p=0.06; Table 1).

There were no significant differences in perinatal maternal or neonatal outcomes, with the exception of increased maternal length of stay on the delivery floor in the IOL group (1464±544 minutes) compared with the EM group (1028±544 minutes; p<0.01; Table 2).

There were no statistically significant differences in indications for cesarean delivery between the 2 groups, including fetal heart rate abnormalities, arrest of descent, and suspected macrosomia. Cesarean deliveries were more likely to have been done for arrest of dilation in the IOL group (64%) compared with the EM group (36%). The difference was not statistically significant, but the study was not designed to be powered to detect a difference in this outcome (Table 3).

Using the analysis criteria stated earlier, the authors of this study concluded that women who received IOL at 39 weeks did not have a statistically significant increase in cesarean delivery compared with those expectantly managed. Larger prospective multicenter studies are needed to produce further evidence on the common practice of elective IOL.

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