695 Cesarean delivery incidence by maternal BMI and diabetes status in multiparous women without prior cesarean

Abstract

To examine the association between body mass index (BMI) and cesarean delivery (CD) in multiparous women without prior CD by diabetes status. This is a retrospective cohort study of multiparous women without prior CD, with singleton, non-anomalous, term pregnancies between 2007 and 2011 using linked vital statistics and discharge data. Chi-square tests were used to compare rates of CD in diabetic and non-diabetic women categorized by BMI class. Pre-pregnancy BMI was categorized into underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2), obesity (30-39.9 kg/m2), and morbid obesity (≥40 kg/m2). Diabetes was classified by pre-existing diabetes, gestational diabetes, and no diabetes. Multivariable logistic regression was used to examine the association of BMI with CD by diabetes classification, controlling for maternal race/ethnicity, age, education, and insurance status. The cohort of 893,965 multiparous women without prior CD consisted of 188,913 (21.1%) obese and morbidly obese pregnant women. A significant association was demonstrated between BMI category and CD for women with pre-existing diabetes, gestational diabetes, and without diabetes (Figure 1). For example, in those with pre-existing diabetes, the risk of CD rose from 14.6% in normal-weight women to 37.9% in those with morbid obesity (p<0.001). After controlling for potential confounders, a higher BMI class was found to be associated with increased odds of CD, independent of diabetes status (Table 1). Further, when compared to women without diabetes, those with gestational and pre-existing diabetes have significantly increased odds of CD (aOR 1.55, 95% CI 1.52-1.59; aOR 2.55 95% CI 2.40-2.71, respectively). Diabetes status and higher BMI category were both found to be individually associated with increased risk of CD in multiparous women without prior CD. This study also demonstrated the compounding effect of diabetes status and obesity on the incidence of CD. Obstetrical education for women in these categories should emphasize the increased potential of this birth outcome.View Large Image Figure ViewerDownload Hi-res image Download (PPT)