Poster Session 3
Category: Labor
Poster Session 3
Minhazur R. Sarker, MD
Fellow Physician
Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Diego
San Diego, California, United States
Grace K. Noonan, MD (she/her/hers)
Obstetrics and Gynecology Resident
Department of Obstetrics, Gynecology and Reproductive Science, University of California San Diego
San Diego, California, United States
Rachel L. Wiley, MD, MPH (she/her/hers)
Maternal Fetal Medicine Fellow
Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Diego
San Diego, California, United States
Daphne Yvette Lacoursiere, MD
Department of Obstetrics, Gynecology and Reproductive Science, University of California San Diego
San Diego, California, United States
Daniella Rogerson, MD, MPH
Department of Obstetrics, Gynecology and Reproductive Science, University of California San Diego
San Diego, California, United States
Timothy Wen, MD, MPH
Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Diego
San Diego, California, United States
Cynthia Gyamfi-Bannerman, MD, MS (she/her/hers)
Professor and Chair
Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California San Diego
San Diego, California, United States
Ukachi N. Emeruwa, MD, MPH (she/her/hers)
Assistant Professor/Women's Reproductive Health Research Scholar
University of California San Diego
San Diego, California, United States
Preterm induction of labor (IOL) is associated with a high perceived baseline rate of failure especially among patients with higher morbidity such as maternal obesity. We aimed to characterize cesarean delivery (CD) rates among preterm IOL stratified by maternal BMI class.
Study Design:
This is a cross-sectional study of United States National Vital Statistics System birth data from 2016-2023 to identify singleton, vertex, non-anomalous pregnancies undergoing preterm IOL between 28w0d-36w6d. The primary exposure and outcome were maternal BMI class at delivery and CD, respectively. Multivariable logistic regression assessed the association between maternal BMI class and CD using normal weight (BMI 18.5-24.9) as the reference. Results were adjusted for maternal age, self-reported maternal race and ethnicity, payer status, gestational age at delivery, diabetes and hypertensive disorders, and macrosomia (birthweight > 4000g).
Results:
499,685 individuals with mean gestational age of 34.8 ± 1.6 weeks met our inclusion criteria: 14,704 (2.8%) underweight, 164,444 (32.9%) normal, 132,516 (26.5%) overweight, 92,683 (18.5%) class I, 52,304 (10.5%) class II, 36,846 (7.4%) class III, 5,896 (1.2%) class IV, and 742 (0.2%) class V. Increasing BMI class was associated with increasing CD rate: 11.4% underweight, 14.2% normal, 17.6% overweight, 21.0% class I, 24.9% class II, 30.7% class III, 36.7% class IV, and 44.2% class V (Figure 1a, p< 0.01). In the adjusted regression, using normal weight as the reference, increasing BMI class was associated with CD (aOR; 95%CI): underweight (0.78; 0.74-0.83), overweight (1.31; 1.29-1.34), class I (1.61; 1.57-1.64), class II (1.94; 1.89-1.99), class III (2.47; 2.40-2.54), class IV (3.00; 2.83-3.19), and class V (3.85; 3.29-4.51) (Figure 2a). When sub-analyzing only nulliparous patients undergoing preterm IOL, higher CD rates were appreciated with stronger associations with CD (Figure 1b and 2b).
Conclusion:
Our findings provide quantitative preterm IOL success rates and highlight that many patients undergoing preterm IOL delivery vaginally.