Dr. Valery A. Danilack, research associate in epidemiology in the Brown University School of Public Health, and colleagues compared expectant management and spontaneous labor approaches in studying the effect of labor induction on cesarean delivery.
[Photo: Dr. Valery A. Danilack]
Labor induction is common in the U.S., and although generally considered safe when there are no contraindications to vaginal delivery, there has been much speculation that labor induction increases the risk of cesarean delivery. Observational studies comparing labor induction to spontaneous onset of labor have found an increased risk of cesarean delivery among induced women. However, when labor induction is compared to expectant management (defined as continuing pregnancies), a decreased risk of cesarean delivery among induced women has been found in some but not all studies. Randomized controlled trials of labor induction versus expectant management have found decreased or no difference in risk of cesarean delivery.
Evidence of the impact of labor induction on cesarean delivery (CD) remains inconclusive because of differing methodological approaches. A spontaneous labor comparison group describes patterns retrospectively, whereas an expectant management comparison group prospectively evaluates a decision to induce. This study examined the influence of comparison group on the association between labor induction and CD.
This study examined 166,559 mother-newborn dyads from 14 National Perinatal Information Center member hospitals, 2007–2012. The study included singleton births 34–42 completed weeks’ gestation and excluded women with contraindications to vaginal delivery. They calculated risk ratios (RR) adjusted for hypertensive and diabetic disorders, intrauterine growth restriction, parity, and maternal age.
Using two different methodological approaches with the same sample, we confirm that comparing labor induction to spontaneous onset of labor, instead of expectant management of pregnancy, does not fully inform clinical practice and may lead to an exaggerated estimate of the risk of CD. Overall, the results suggest that labor induction does not independently increase the risk of cesarean delivery considerably.
The study was published in April in Annals of Epidemiology, Vol 26, Issue 4.