Contemporary labor patterns: the impact of maternal body mass index
journal contributionposted on 2012-06-27, 00:00 authored by Michelle A. Kominiarek, Jun Zhang, Paul VanVeldhuisen, James Troendle, Julie Beaver, Judith U. Hibbard
Objective: To compare labor patterns by body mass index (BMI). Study Design: 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 that reached 10cm. 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 (3.4hours) compared to BMI<25.0 (2.4hours). Progression by centimeter (P<0.001 for nulliparas) and from 4-10cm (P<0.001 for nulliparas and multiparas) increased as BMI increased. Second stage length with and without an epidural was similar among BMI categories for nulliparas (P>0.05), but decreased as BMI increased for multiparas (P<0.001). Conclusion: Labor proceeds more slowly as BMI increases suggesting that labor management be altered to allow longer time for these differences.
This study was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, through a contract (Contract No. HHSN267200603425C) and by Grant Number K12HD055892 from the NICHD and NIH Office of Research on Women’s Health (ORWH).
Publisher StatementNOTICE: this is the author’s version of a work that was accepted for publication in American Journal of Obstetrics and Gynecology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in American Journal of Obstetrics and Gynecology, Vol 205, Issue 3, September 2011. DOI: 10.1016/j.ajog.2011.06.014. The original publication is available at www.elsevier.com.