Association between pre-pregnancy obesity and the risk of cesarean delivery.

OBJECTIVE: To explore the relationship between pre-pregnancy obesity and the risk for cesarean delivery.

METHODS: The population studied included 20,130 women with live births after 20 weeks' gestation in central New York state between June 1, 1994, and May 31, 1995. Women who were obese before pregnancy were compared with nonobese women with regard to mode of delivery. Obesity was defined as body mass index (BMI) greater than 29. Separate analyses were conducted on the entire sample and on a subset of women with singleton pregnancies and no prior cesarean deliveries, as an estimate of the risk of primary cesarean delivery in obese women. Statistical analyses included chi 2 test, crude odds ratio (OR) with 95% confidence interval (CI), and adjusted OR with 95% CI, using logistic regression to control for confounding variables.

RESULTS: The adjusted OR was 1.64 (95% CI 1.46, 1.83) for obese women with singleton pregnancies and no prior cesarean deliveries to undergo cesarean delivery. The adjusted OR was 1.66 (95% CI 1.51, 1.82) for obese women in the entire sample to undergo cesarean delivery. In addition, increasing BMI was associated with increased risk for cesarean delivery.

CONCLUSION: Compared with nonobese women, women who are obese before pregnancy are at increased risk for cesarean delivery. Preconceptional counseling regarding dietary and life-style modifications may alter this pattern.