Maternal overweight and obesity as independent risk factors for cesarean delivery

Abstract

Introduction: Overweight and obesity both are associated with an increased risk of cesarean section. Since this increased risk could be biased by confounding variables such as diabetes or hypertension, in this study we aim to determine whether this risk persists after adjusting for numerous control variables.Objective: To determine if maternal overweight and/or obesity are independent risk factors to cesarean section.Methods: Retrospective cohort study. We included pregnant women from the University Hospital of Puerto Real. Period of study: 2002-2011. Two study groups were included: overweight at the beginning of the gestation (BMI between 25 and 29.9 kg/m(2)) and obesity at the beginning of the gestation (BMI >= 30 kg/m(2)). Control group: pregnant women with normal BMI at the beginning of the gestation (Between 18.5 and 24.9 kg/m(2)). Multiple logistic regression analysis was conducted in order to evaluate the risk of caesarean. The variables included in the model were maternal age, induced labor, diabetes (gestational and pregestational), macrosomia, arterial hypertension, nulliparous, previous caesarean section, preterm birth and post-term childbirth.Results: Initial BMI was registered in 4,711 cases (25.8%) of a total of 18,243 births. Of these, 26.1% were overweight; 12.4% obesity and 58.9% normal BMI. Without adjusting by control variables, both overweight and obesity are associated to an increase in the risk of caesarean section: overweight (OR 1.48; CI95% 1.27-1.73); type 1 obesity (OR 2.09; CI95% 1.66-2.64); type 2 obesity (OR 3.23; CI95% 2.31-4.53); type 3 obesity (OR 2.57; IC95% 1.56-4.22). The risk remained significantly increased in the multivariate analysis: overweight (OR 1.51; CI95% 1.24-1.84); obesity (OR 2.15; IC95% 1.67-2.76).Conclusions: In conclusion, a significant and independent association was found between maternal overweight/obesity and cesarean section, even including numerous control variables such as age, nulliparous, previous cesarean section, hypertension, diabetes, birth weight and gestational age at birth.