Abstract
BACKGROUND: Gestational weight gain (GWG) proportional to body mass index before pregnancy is one of the factors on maternal and neonatal outcomes. The aim of the current study was to assess association between GWG, and cesarean section, birth weight and gestational age at birth in women with normal BMI prior to pregnancy. METHODS: This was a cross-sectional study carried out in 103 hospitals in Tehran, the capital of Iran, from July 6 to 21, 2015. The data were extracted by 103 trained midwives. Finally, 2394 pregnant women with normal BMI before pregnancy and singleton birth were examined. GWG was categorized based on Institute of Medicine (IOM) recommendations. RESULTS: Prevalence of low birth weight (LBW) was 5.41% and prevalence of macrosomia was 2.18%. The prevalence of LBW in women with GWG less than the weight gain recommended by IOM was 2.13 times [95% confidence interval (CI) 1.13-4.02, P = 0.019] more than in women with GWG equal to the weight gain recommended by IOM. There was no statistically significant difference in the prevalence of LBW between women with GWG more than recommended weight gain by IOM and women with GWG equal to the weight gain recommended by IOM (OR = 1.21, 95% CI 0.61-2.38, P = 0.580). CONCLUSION: After controlling for confounding variables, the prevalence of cesarean section and preterm birth had no significant difference at various levels of GWG. Accordingly, the prevalence of LBW among women with GWG less than the recommended weight gain by IOM was significantly 2.13 more than that among women with GWG equal to the recommended weight gain by IOM.