Category: Labor
Poster Session IV
To describe normal progression through cervical ripening and determine the effect of pre-pregnancy body mass index (BMI) on ripening duration and outcomes
Study Design:
A retrospective cohort study of patients undergoing term induction of labor at one academic hospital from 1/1/2020 to 12/31/2021. Nulliparous, term, singleton pregnancies were included. The primary outcome was duration of cervical ripening. The secondary outcome was probability of vaginal delivery with increasing cervical ripening duration per BMI group. The primary predictor was pre-pregnancy BMI category: normal weight (BMI 18.5 – 24.9 kg/m2), overweight (BMI 25.0 – 29.9), and obese (BMI > 30).
Results:
5712 total charts were reviewed and 1031 patients met the inclusion criteria. Of these, 34.2% were normal weight, 31.3% overweight, and 34.4% were obese. There were statistically different self-reported races in BMI groups. Gestational age significantly decreased, and birth weight increased by increasing BMI group (p= < 0.05). The average duration of time spent in cervical ripening for all patients was 15.5 hours. Compared to the total ripening time for normal weight patients (mean 13.4 hours ± 9.5 hours), overweight patients required 1.82 hours longer (95% CI 0.07-3.57, p=0.04) and obese patients required 4.45 additional hours (95% CI 2.74-6.16, p= < 0.001) (Figure 1). In a Kaplan-Meier Survival analysis, median hours of cervical ripening to achieve vaginal delivery is significantly increased with each increasing BMI category (normal weight 13.7 versus overweight 14.5 versus obese 19.0, p= < 0.001) (Figure 2). Compared to normal weight patients, those in the overweight and obese group were less likely to have a vaginal delivery at any cervical ripening timepoint (24% less p=0.004, vs 39%, p= < 0.001, respectively).
Conclusion:
Overweight and obese patients required progressively longer durations of cervical ripening compared with normal weight patients. For any given cervical ripening duration, those with pre-pregnancy BMI either overweight or obese were less likely to achieve vaginal delivery.
Rachel C. Taylor, MD (she/her/hers)
Resident Physician
Division of Maternal-Fetal Medicine, University of Massachusetts Memorial Medical Center
Worcester, Massachusetts, United States
Courtney L. Birchall, MD
University of Massachusetts Memorial Medical Center, Division of Maternal-Fetal Medicine
Worcester, Massachusetts, United States
Rohini Loke, BS (she/her/hers)
Medical Student
UMass Chan Medical School
Worcester, Massachusetts, United States
Taylor Dickinson, BS, MS
University of Massachusetts Chan Medical School
Worcester, Massachusetts, United States
Stewart G. Maxfield, BS
University of Massachusetts Chan Medical School
Worcester, Massachusetts, United States
Catherine Merton, BS
University of Massachusetts Chan Medical School
Worcester, Massachusetts, United States
Katherine Leung, MPH
Biostatistician
Department of Obstetrics and Gynecology, University of Massachusetts Medical School
Worcester, Massachusetts, United States
Heidi K. Leftwich, DO
University of Massachusetts
Worcester, Massachusetts, United States