Prostaglandin versus mechanical dilation and the effect of maternal obesity on failure to achieve active labor: a cohort study

Abstract

Purpose: Assess the impact of obesity on successful cervical ripening with mechanical versus prostaglandin ripening.

Materials and methods: We compared obese to non-obese women in an analysis stratified by induction method, prostaglandin versus mechanical. Misoprostol dosing was the same for obese and non-obese women. Pitocin was titrated to effect. Our primary outcome was failure to achieve active labor. Secondary outcomes included overall cesarean delivery rate, doses of misoprostol used and need for protocol deviation.

Results: Obese women had a higher cesarean delivery rate with misoprostol (35% versus 26%, p = 0.03) but not with mechanical ripening (31% versus 29%, p = 0.69). Obesity was associated with a higher rate of failure to achieve active labor in women undergoing prostaglandin ripening with misoprostol (24 versus 15%, p = 0.01) but not in women undergoing mechanical ripening (19 versus 15%, p = 0.55). After controlling for confounding variables, obese women who underwent cervical ripening with misoprostol had a higher rate of failure to achieve active labor, aOR 1.29 (95%CI: 1.00–1.67), which was not seen with mechanical ripening, aOR 1.09 (95%CI: 0.69–1.73).

Conclusion: Obese women receiving the same dose of misoprostol as non-obese women have higher rates of failure to achieve active labor, an effect not seen with mechanical ripening.

Keywords:

• Misoprostol
• induction
• cervical ripening
• obesity

Acknowledgements

Study data were collected and managed with REDCap Software (Research Electronic Data Capture), which is hosted at the Cincinnati Children’s hospital Medical Center under the Center for Clinical Translational Science and Training grant support (UL1-RR026314-01 NCRR/NIH). REDCap is a secure, web-based application that was designed to support data capture for research studies to provide (1) an intuitive interface for validated data entry, (2) audit trails for tracking data manipulation and export procedures, (3) automated export procedures for seamless data downloads to common statistical packages, and (4) procedures for importing data from external sources.

Declaration of interest

The authors have no conflicts of interest or financial disclosures. They all contributed to the production of this manuscript.

This research was approved by our Institutional Review Board (Protocol Number #11092706).

This research was accepted for oral presentation at the Central Association of Obstetrics and Gynecology annual meeting, Charleston, SC, USA, October 2015.

This research is not under consideration elsewhere and will not be submitted elsewhere pending decision.

This study was approved by the University of Cincinnati Institutional Review Board.

This study was not funded internally or externally.