The Association Between Preconception Body Mass Index and Pregnancy Weight gain on Birth Weight

Background and The newborn birth weight is an important indicator for prenatal care, general health and fetal viability. The aim of this study was to assess the relationship between pre-pregnancy BMÏ and pregnancy weight gain on neonatal birth weight. Ïn a descriptive-analytical study, 16-40 years old pregnant mothers registered to prenatal clinics of Lowlagar and Mahdieh Hospitals in Tehran in the year 2009 were studied. Simple sampling method was used. Weight gain during prenatal visits was recorded and mothers were followed up for maternal-fetal outcomes till delivery. The association between primary BMÏ, total pregnancy weight gain and birth weight was assessed by multivariate regression model. 1084 eligible mothers with singleton, low risk pregnancy were studied. There was a statistically significant relationship between pre-pregnancy BMÏ and pregnancy weight gain and newborn birth weight (p<0.05). Ïn addition, maternal weight gain during pregnancy and neonate birth weight were related (p<0.001). Results of linear regression analysis showed that gestational age at birth, total pregnancy weight gain and pre-pregnancy BMÏ were effectual in prediction of the neonate birth weight, with the gestational age at the time of labor having the highest impact on neonatal weight at birth (p<0.05).Çonclusion: Based on the results, pregnancy weight gain regardless of pre-pregnancy BMÏ affects newborn birth weight. Therefore, appropriate maternal weight gain during pregnancy should be emphasized in support of neonatal health.