FINDINGS:

Walker and colleagues designed their study (NEJM, 2016) to determine whether induction of labor to prevent stillbirth at term in primigravid women age 35 years or older increases the risk of cesarean section. 619 women were randomized to either induction at 39w0d and 39w6d of gestation or waiting for spontaneous onset of labor or induction for a medical indication. Monitoring in the control group was based on physician preference. Women could undergo induction between 41w0d and 42w0d. The researchers found:

There was no difference in the induction vs. control group for the following outcomes:

• Percentage of women undergoing cesarean section (primary outcome) 
• Percentage of women undergoing vaginal delivery requiring forceps or vacuum
• Maternal or infant deaths (zero events in both groups)
  • Authors are clear that the study was not necessarily large enough to determine if induction prevents stillbirths
• Maternal childbirth experience
  • 83% response rate to questionnaire that assesses level of satisfaction with the birth experience
• Frequency of adverse maternal or neonatal outcomes

SYNOPSIS:

There is increased risk of adverse outcomes in women 35 years of age and older, including stillbirth at term. Cesarean section at 39 weeks could potentially be a preventative option. Women were not eligible for this study if they had complications such as a known lethal congenital anomaly, contraindications to labor, vaginal delivery or expectant management due to maternal medical complications such as gestational diabetes. Prior studies on the subject suggested increased risk of cesarean section as a result of induction, but were observational, not randomized.

KEY POINTS:

• This study may not be generalizable to multiparous women or those at high risk
• This study is consistent with previous well designed studies that indicate induction at term for other indications does not result in increased cesarean section rates or poor maternal or neonatal outcomes
• The authors have demonstrated the safety of proceeding with a larger randomized trial to determine if induction at term for women 35 years or older may truly prevent stillbirths

Learn More – Primary Sources:

NEJM: Randomized Trial of Labor Induction in Women 35 Years of Age or Older

Related ObG Topics:

Labor induction and an unripe cervix: does it result in more C-sections?

Misoprostol or Foley catheter for an unfavorable cervix at term?

Hypertension at 34 – 37 weeks: immediate delivery or wait?

Levels of Evidence – How to Rate the Quality of a Study