FPIN's Help Desk Answers
Maternal Obesity and Labor Induction
Am Fam Physician. 2018 May 15;97(10):671-672.
Is maternal obesity associated with failure of induction of labor?
Pregnant women who are obese have nearly double the rate of cesarean delivery, and obesity increases the median duration of active labor by up to four hours when labor is induced. The difference in cesarean delivery rate is larger in obese primigravida patients presenting with cervical dilation of less than 1 cm. (Strength of Recommendation: B, based on a secondary analysis of a randomized controlled trial and cohort studies.)
A 2009 secondary analysis of data from a previous double-blind randomized controlled trial compared two types of vaginal prostaglandins.1 The study included 1,273 women requiring cervical ripening (Bishop score less than 5). They were stratified by body mass index (BMI) into lean, obese, and extremely obese (BMI less than 30 kg per m2, 30 to 39.9 kg per m2, and 40 kg per m2 or more, respectively). Patients were older than 17 years with singleton pregnancies of at least 36 weeks' gestation, less than four previous deliveries, and no previous cesarean deliveries. Intravaginal dinoprostone (Cervidil) or misoprostol (Cytotec) was used for cervical ripening. Rates of cesarean deliveries for any indication were 21% in the lean group, 30% in the obese group (odds ratio [OR] = 1.6; 95% confidence interval [CI], 1.2 to 2.1), and 37% in the extremely obese group (OR = 2.1; 95% CI, 1.5 to 3.5). Median duration of active labor was significantly longer in both obese groups (16 hours in obese and 19 hours in very obese, compared with 15 hours in the lean group (P < .001 for both comparisons). This was confirmed after adjusting for race, parity, and type of prostaglandin used.
A 2015 retrospective cohort study of 7,543 women with singleton term pregnancies undergoing labor induction examined the association between BMI and cesarean delivery rate.2 Indications for induction were classified as maternal, fetoplacental, postdates, rupture of membranes,
1. Pevzner L, Powers BL, Rayburn WF, Rumney P, Wing DA. Effects of maternal obesity on duration and outcomes of prostaglandin cervical ripening and labor induction. Obstet Gynecol. 2009;114(6):1315–1321.
2. Ronzoni S, Rosen H, Melamed N, Porat S, Farine D, Maxwell C. Maternal obesity class as a predictor of induction failure: a practical risk assessment tool. Am J Perinatol. 2015;32(14):1298–1304.
3. O'Dwyer V, O'Kelly S, Monaghan B, Rowan A, Farah N, Turner MJ. Maternal obesity and induction of labor. Acta Obstet Gynecol Scand. 2013;92(12):1414–1418.
Help Desk Answers provides answers to questions submitted by practicing family physicians to the Family Physicians Inquiries Network (FPIN). Members of the network select questions based on their relevance to family medicine. Answers are drawn from an approved set of evidence-based resources and undergo peer review. The strength of recommendations and the level of evidence for individual studies are rated using criteria developed by the Evidence-Based Medicine Working Group (http://www.cebm.net).
The complete database of evidence-based questions and answers is copyrighted by FPIN. If interested in submitting questions or writing answers for this series, go to http://www.fpin.org or e-mail: email@example.com.
This series is coordinated by John E. Delzell Jr., MD, MSPH, Associate Medical Editor.
A collection of FPIN's Help Desk Answers published in AFP is available at https://www.aafp.org/afp/hda.
Want to use this article elsewhere? Get Permissions