The Impact of Body Mass Index on Pregnancy Outcome

Pre-pregnancy obesity is considered as a significant predictor for neonatal and maternal morbidity and mortality. Several studies have indicated conflicting associations between body mass index (BMI) and pregnancy outcomes. This study aimed to evaluate the effects of pre-pregnancy BMI on adverse pregnancy outcomes. Thiscohort study was conducted from 2010 to 2013 in Qazvin province, Iran. BMI was measured in a total of 1376 pregnant women before their 12th week of pregnancy. The subjects were followed-up until the termination of their pregnancy and childbirth. Data collection was performed through checklists prepared by the researchers, which consisted of three parts: demographic features, obstetric history, and subsequent pregnancy outcome. For data analysis, Chi-square, ANOVA and Mann-Whitney tests were performed, using SPSS version 16. In addition, adjusted odds ratio (OR) and 95% confidence interval (CI) were measured. The risk of preeclampsia (OR: 5.36, CI: 2.505-11.49), gestational diabetes mellitus (OR: 5.092, CI: 1.67-15.46), cesarean section (OR: 1.959, CI: 1.37-2.79), and large for gestational age (OR: 4.735, CI: 1.402-15.98) was higher in overweight (25≤BMI≤29.9 kg/m2) and obese groups (BMI>30 kg/m2), compared to women with below-normal and average weight. Pre-pregnancy obesity is strongly associated with certain pregnancy complications and perinatal conditions. Therefore, these complications implicate the need for pre-pregnancy counseling and weight loss in this group of women.