The Dose-Dependent Effect of Obesity on Adverse Maternal and Neonatal Outcomes in a Hispanic Population.

Objective: To evaluate the frequency of adverse maternal and neonatal outcomes associated with maternal obesity in a Hispanic population. We hypothesized that obesity confers a dose-dependent risk associated with these outcomes.

Study design: This was a retrospective cohort study of singleton pregnancies delivered between 24 and 42 weeks gestation at an urban county hospital between 2013 and 2021. Body mass index (BMI) at first prenatal visit was used as a proxy for pre-pregnancy weight. Patients were excluded if their first trimester BMI was not available. Trends in adverse outcomes across increasing obesity classes were assessed.

Results: During the study period, 58,497 patients delivered a singleton infant, of which 12,365 (21.1%), 5429 (9.3%), and 3482 (6.0%) were in class I, II, and III obesity, respectively. Compared with non-obese patients, more obese patients were more likely to be younger and nulliparous with a higher incidence of hypertension and pregestational diabetes. Higher BMI was associated with a significant dose-dependent increase in cesarean delivery (27% for non-obese, 34% for class I, 39% for class II, and 46% for class III obesity); severe preeclampsia (8% in non-obese and 19% for class III obesity); and gestational diabetes (5% in non-obese and 15% in class III obesity). There were significant trends in increasing morbidity for infants born to patients with correspondingly higher obesity classes. Some of these adverse outcomes included respiratory distress syndrome, neonatal intensive care unit admission, fetal anomalies, and sepsis (all p < 0.001).

Conclusion: Increasing body mass index is associated with a significant dose-dependent increase in multiple adverse perinatal outcomes in a Hispanic population. Associated adverse maternal outcomes include severe preeclampsia, gestational diabetes, and cesarean delivery. Infants born to patients with correspondingly higher BMI class have significantly increased associated morbidity. Often, only higher BMI classes are significantly associated with these adverse outcomes.