The effect of prepregnancy body mass index on birth weight, preterm birth, cesarean section, and preeclampsia in pregnant women

Abstract

Objective: The objective of this study is to determine the impact of maternal prepregnancy BMI on birth weight, preterm birth, cesarean section, and preeclampsia among pregnant women delivering singleton life birth.Methods: A cross-sectional study of 4397 women who gave singleton birth in Tehran, Iran from 6 to 21 July 2015, was conducted. Women were categorized into four groups: underweight (BMI < 18.5 kg/m2), normal (BMI 18.5–25 kg/m2), overweight (BMI 25–30 kg/m2) and obese (BMI >30 kg/m2), and their obstetric and infant outcomes were analyzed using both univariate and multivariate logistic regression.Results: Prepregnancy BMI of women classified 198 women as underweight (4.5%), 2293 normal (52.1%), 1434 overweight (32.6%), and 472 as obese (10.7%). In comparison with women of normal weight, women who were overweight or obese were at increased risk of preeclampsia (odds ratio (OR) = 1.47, 95% CI = 1.06–2.02; OR = 3.67, 95% CI = 2.57–5.24, respectively) and cesarean section (OR = 1.21, 95% CI = 1.04–1.41; OR = 1.35, 95% CI = 1.06–1.72, respectively). Infants of obese women were more likely to be macrosomic (OR = 2.43, 95% CI = 1.55–3.82).Conclusion: Prepregnancy obesity is a risk factor for macrosomia, preeclampsia, and cesarean section and need for resuscitation.