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Updated: May 20, 2026

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development
Published on: January 26, 2018
Maternal obesity and contraction strength in the first stage of labor
Jeanette R Chin1, Erick Henry, Calla M Holmgren
1Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Utah School of Medicine, Salt Lake City, USA. jeanette.chin@hsc.utah.edu
Objective:
The purpose of this study was to determine whether maternal obesity is associated with cesarean delivery and decreased contraction strength in the first stage of labor.
Study Design:
We studied a retrospective cohort of women who delivered within a single healthcare system from 2007-2009; we included 5410 women with an intrauterine pressure catheter during the last 2 hours of the first stage of labor and who either had a vaginal delivery or cesarean delivery for dystocia. Logistic regression was used to determine how body mass index was associated with cesarean delivery or mean Montevideo units of ≥200.
Results:
Although obese women were at significantly greater odds of cesarean delivery than normal-weight women (odds ratio, 2.4; 95% confidence interval, 1.9-3.1), they were equally able to achieve Montevideo units of ≥200. Among women with a vaginal delivery, obese women had a longer first stage of labor compared with normal-weight women (597 vs 566 min; P = .003).
Conclusion:
Obese women have longer labors but are equally able to achieve adequate Montevideo units as normal-weight women.
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