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Updated: May 30, 2026

External Cephalic Version: Is it an Effective and Safe Procedure?
Published on: June 6, 2020
Contemporary labor patterns: the impact of maternal body mass index
Michelle A Kominiarek1, Jun Zhang, Paul Vanveldhuisen
1Department of Obstetrics and Gynecology, University of Illinois at Chicago, Chicago, IL, USA. Mkomin1@uic.edu
Objective:
We sought to compare labor patterns by body mass index (BMI).
Study Design:
A total of 118,978 gravidas with a singleton term cephalic gestation were studied. Repeated-measures analysis constructed mean labor curves by parity and BMI categories for those who reached 10 cm. Interval-censored regression analysis determined median traverse times, adjusting for covariates in vaginal deliveries and intrapartum cesareans.
Results:
In the labor curves, the time difference to reach 10 cm was 1.2 hours from the lowest to highest BMI category for nulliparas. Multiparas entered active phase by 6 cm, but reaching this point took longer for BMI ≥40.0 (3.4 hours) compared to BMI <25.0 (2.4 hours). Progression by centimeter (P < .001 for nulliparas) and from 4-10 cm (P < .001 for nulliparas and multiparas) increased as BMI increased. Second stage length, with and without an epidural, was similar among BMI categories for nulliparas (P > .05) but decreased as BMI increased for multiparas (P < .001).
Conclusion:
Labor proceeds more slowly as BMI increases, suggesting that labor management be altered to allow longer time for these differences.
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