Increasing body mass index is associated with intensive care unit admission and severe maternal morbidity

ObjectiveThis study aimed to assess the relationship between increased body mass index (BMI) with severe maternal morbidity (SMM). Study DesignWe obtained data for a retrospective cohort of singleton live births using an electronic birth certificate database from 2010 to 2022 in Central New York. Institutional review board exemption was obtained. Pre-pregnancy BMI was assessed as a continuous variable and a categorical variable with groups of BMI <18.5 kg/m2, 30-39.9 kg/m2, 40-49.9 kg/m2, and >= 50 kg/m2 compared to patients with BMI 18.5-29.9 kg/m2. Primary outcomes were maternal intensive care unit (ICU) admission and composite SMM defined as ICU admission, unplanned hysterectomy, reoperation, eclampsia, and blood transfusion. Secondary outcomes were the individual SMM components, 5-minute APGAR score <7, and neonatal intensive care unit (NICU) admission. ANOVA and chi 2 were used to compare continuous and categorical variables respectively, and logistic regression was used to obtain adjusted odds ratios for primary and secondary outcomes. ResultsThere were 223,837 patients with singleton live births with mean BMI 27.86 kg/m2. 54,385 (24.3%) had BMI 30-39.9 kg/m2, 13,299 (5.9%) had BMI 40-49.9 kg/m2, and 1,958 (0.87%) had BMI >= 50 kg/m2. 3,203 (1.4%) patients experienced SMM, and 423 (0.2%) patients were admitted to ICU. For each 1-point increase in BMI the adjusted odds ratio (aOR) of SMM increased by 0.8% (aOR 1.008, 95% CI 1.002-1.013) and ICU admission increased by 2.0% (aOR 1.02, 95% CI 1.005-1.034). Odds of ICU admission for those with BMI 40-49.9 kg/m2 increased by 69% (aOR 1.69, 95% CI 1.16-2.47); BMI >= 50 kg/m2 increased by 300% (aOR 3.01, 95% CI 1.53-5.91), but those with BMI 30-39.9 kg/m2 did not have significantly higher odds of ICU admission (aOR 1.09, 95% CI 0.84-1.42). ConclusionIncreasing BMI was significantly associated with increased SMM and maternal ICU admission.