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Clinical Obstetrics

Poster Session 1

(230) Trial of Labor or Repeat Caesarean Delivery in Women With Morbid Obesity

Tuesday, February 13, 2024
10:30 AM – 12:00 PM  
Location: Prince George's Exhibit Hall CDE, Lower Atrium Level
Objective: Given that obesity affects vaginal delivery rates (VD), which impact trial of labor after cesarean (TOLAC) success and safety, we aimed to evaluate the impact of BMI on adverse neonatal outcomes associated with TOLAC, after accounting for prior VD.

Study Design:

This was a repeated cross-sectional analysis of individuals with singleton, cephalic, and term deliveries with a history of one or two cesarean deliveries in the Linked Birth/Infant Death data from 2011 to 2020. Outcomes were examined according to the BMI category including BMI < 30, 30-39.9, and 40-69.9 kg/m2. The primary outcome was a composite neonatal outcome, defined as any presence of neonatal death, neonatal intensive care unit admission, assisted ventilation, surfactant therapy, or seizures. Outcomes were compared between TOLAC and elective repeat cesarean delivery (eRCD) after stratifying by BMI category and previous VD. Log-binomial regression was performed to obtain adjusted relative risk (aRR) with 99% confidence intervals, controlling for covariates.

Results:

Of 4,055,440 individuals, 2,627,131 had BMI< 30, 1,108,278 had BMI 30-39.9, and 320,031 had BMI 40-69.9 kg/m2. In individuals with no prior VD, VD rates after TOLAC were 66.7%, 57.2%, and 48.1%, respectively. In individuals with prior VD, VD rates after TOLAC were 81.4%, 74.7%, and 67.3%, respectively. In the subgroup without prior VD, TOLAC was associated with the primary outcome in individuals with BMI < 30 kg/m2 (5.0% vs. 6.5%; aRR 1.33 [1.30-1.36]), BMI 30-39.9 kg/m2 (6.2% vs. 7.8%; aRR 1.29 [1.24-1.34]), and BMI 40-69.9 kg/m2 (8.2% vs. 9.0%; aRR 1.15 [1.07-1.23]) compared with eRCD. In the subgroup with prior VD, there were no differences in the primary outcomes between TOLAC and eRCD across BMIs (BMI < 30:  (6.2% vs.5.8%; aRR 0.98 [0.96-1.00]), BMI 30-39.9:  (7.4% vs.7.1%; aRR 0.99 [0.95-1.02]), and BMI 40-69.9: (9.4% vs. 8.7%; aRR 0.96 [0.91-1.02]). 

Conclusion:

Neonatal outcome in TOLAC is impacted by prior VD rather than BMI. Prior studies regarding the safety of TOLAC in obese patients are likely confounded by prior VD.