Influence of Maternal Obesity on Labor Induction: A Systematic Review and Meta-Analysis

Abstract

Introduction: Studies have shown that women with obesity have longer labors. The purpose of this systematic review and meta-analysis is to examine existing evidence regarding labor induction in women with obesity, including processes and outcomes. The primary outcome was cesarean birth following labor induction. Secondary outcomes were the timing and dosage of prostaglandins, the success of mechanical cervical ripening methods, and synthetic oxytocin dose and timing.

Methods: Searches were performed in PubMed, MEDLINE, Embase, CINAHL, EBSCO, the Cochrane Database of Systematic Reviews, the Database of Abstracts of Effects, Google Scholar, and ClinicalTrials.gov. Searches were limited to studies published in English after 1990. Ten studies published between 2009 and 2017 were included in this review. All were observational studies comparing processes and outcomes of induction of labor in relation to maternal body mass index. The primary outcome was cesarean birth following labor induction. We assessed heterogeneity using Cochran's Q test and tau-squared and I² statistics. We also calculated fixed-effect models to estimate pooled relative risks and weighted mean differences.

Results: Ten cohort studies met inclusion criteria; 8 studies had data available for a meta-analysis of the primary outcome. Cesarean birth was more common among women with obesity compared with women of normal weight following labor induction (Mantel-Haenszel fixed-effect odds ratio, 1.82; 95% CI, 1.55-2.12; P < .001). Maternal obesity was associated with a longer time to birth, higher doses of prostaglandins, less frequent success of cervical ripening methods, and higher dose of synthetic oxytocin, as well as a longer time to birth after oxytocin use.

Discussion: Women with obesity are more likely than women with a normal weight to end labor induction with cesarean birth. Additionally, women with obesity require longer labor inductions involving larger, more frequent applications of both cervical ripening methods and synthetic oxytocin.

Keywords: cervical ripening; induction of labor; intrapartum; obesity; oxytocin; prostaglandins; transcervical catheters.