296 Incidence of stillbirth by maternal body mass index and diabetes status

Abstract

OBJECTIVE: To examine the association between body mass index (BMI) and preeclampsia in women with pre-existing diabetes, gestational diabetes, and without diabetes. STUDY DESIGN: This is a retrospective cohort study of women 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 preeclampsia 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). Multivariable logistic regression was used to examine the association of BMI with preeclampsia by diabetes classification, controlling for maternal race/ethnicity, age, parity, education, and insurance status. RESULTS: The cohort of 1,859,198 consisted of 364,392 (19.6%) obese pregnant women. Overall, a higher BMI class was associated with increased odds of preeclampsia, independent of diabetes status. Overweight BMI had an adjusted odds ratio (aOR) of 1.67, obese BMI had an aOR of 2.46, and morbidly obese BMI had an aOR of 3.62 all when compared to normal weight women, regardless of diabetes status (Table 1). Underweight pre-pregnancy BMI was associated with decreased odds of preeclampsia (aOR 0.76) compared to normal weight women. When compared to women without diabetes, those with gestational and pre-existing diabetes have significantly increased odds of preeclampsia (aOR 1.81, 95% CI 1.77-1.86 and aOR 3.10 95% CI 2.96-3.25, respectively). A significant compounding association was demonstrated between BMI category and preeclampsia for women with pre-existing diabetes, gestational diabetes, and without diabetes (Figure 1). CONCLUSION: Diabetes status and higher BMI category were found to be individually associated with increased odds of preeclampsia. This study also demonstrated the compounding effect of diabetes and obesity on incidence of preeclampsia. Obstetrical education for women in these categories should emphasize the increased potential of this adverse outcome.