Objective: The purpose of this study was to evaluate the association between cesarean delivery rate and body mass index (BMI) for the patient population served by the University of Tennessee Medical Center in Knoxville, TN.
Study design: A retrospective, cohort study was conducted using the perinatal birthlog fromJanuary 1, 2009 through December 31, 2009. The database totaled 2,399 women. Women who delivered > or = 23 weeks gestational age were included. Those missing data imperative to our study (height, weight, mode of delivery) were excluded. Thus, our study included 2,235 women. Cesarean delivery rate was calculated for each of the five BMI categories. Univariate analysis using Chi square, Mann-Whitney U test and independent t-test were used to describe associations between body mass index, mode of delivery and other independent variables. Additional analyses were made on the subset of nulliparous women.
Results: Using prepregnancy BMI, 6.7 percent of our population was underweight, 44.3 percent normal weight, 22.6 percent overweight, 20.6 percent obese, and 5.8 percent morbidly obese. The overall cesarean delivery rate was 36.2 percent. Twenty-six percent of underweight and 31.4 percent of normal weight women required cesarean delivery, while 39.1 percent of overweight, 40.8 percent of obese and 56.6 percent of morbidly obese women required cesarean delivery. In addition to cesarean delivery, hypertensive disorders (OR 3.29; 95% CI 2.51-4.31) and diabetes (OR 5.27; 95% CI 3.73-7.44) complicated significantly more pregnancies of obese women than normal weight women.
Conclusion: There was an increased rate of cesarean delivery as BMI increased. Increased BMI is also associated with other pregnancy complications, including hypertensive disorders and diabetes.