(580) The association between obesity and post-cesarean morbidity

Severe maternal morbidity (SMM) and pregnancy-related deaths are increasing, which may be affected in part by the rising prevalence of maternal obesity and rates of cesarean delivery (CD). Although each is an independent risk factor for maternal morbidity, obesity is also an established risk factor for CD. The objective of this analysis is to evaluate the relationship between body mass index (BMI) in pregnancy and SMM and mortality among individuals who underwent CD.

Study Design:
Secondary analysis of a multicenter trial of tranexamic acid (TXA) in individuals who underwent CD. We included those with a documented BMI >18.5 kg/m² prior to 20 weeks’ gestation. The primary exposure was categorical BMI: normal (18.5-24.9 kg/m²) [referent], overweight (25-29.9 kg/m²), class I/II obesity (30-39.9 kg/m²), class III obesity (≥40 kg/m²). The primary outcome was a composite of SMM and mortality including blood transfusion, acute kidney injury, hysterectomy, venous thromboembolism, ischemic stroke, myocardial infarction, seizure, sepsis, ICU admission, or death. We also evaluated individual adverse outcomes including postpartum infection, postpartum hemorrhage with interventions, and hospital readmission. Multivariable logistic regression was used to adjust for potential confounding variables.

Results:
A total of 8,864 individuals were included in this analysis. There was no difference in the primary outcome across BMI groups. There were significantly higher odds of the primary outcome excluding blood transfusion (aOR[95%CI]: 1.89[1.05, 3.40]), postpartum infection (2.05[1.36, 3.10]) and blood loss >1 liter (1.81[1.37, 2.40]) with class III obesity, and of hospital readmission with class I/II (1.61[1.16, 2.23]) and class III obesity (2.29[1.59, 3.28]).

Conclusion:
There was not an observed association between BMI and the primary outcome; however, class III obesity was associated with SMM/mortality when blood transfusion was excluded from the composite. The higher odds of important secondary outcomes in class III obesity highlight the risk for maternal morbidity in this cohort.