The Effect of Prepregnancy Body Mass Index and Weight Gain during Pregnancy on Infant Birth Weight

ABSTRACT

BACKGROUND: To examine the effect of weight gain during pregnancy and prepregnancy body mass index on infant birth weight in normal term pregnancy. METHODS: We analyzed the weight data from 501 women who were in healthy singleton term pregnancy in a general hospital in Seoul from Jan. 2001 to Jun. 2001. Among the 501 women, 209 women whose data were available to calculate weight gain in every trimester were chosen. To study the effect of maternal weight gain on infant birth weight, multiple regression analysis, controlled for selected covariables, was carried out on the entire sample and on each prepregnancy weight group. RESULTS: In all the subjects both prepregnancy body mass and weight gain significantly influenced birth weight. For the lower and normal BMI, each kilogram of maternal weight gain significantly increased birth weight. CONCLUSION: These observations supports the recent evidence for the association between maternal weight gain and birth weight, but only for woman whose prepregnancy BMI are lower and normal. High maternal prepregnancy BMI did not have any influence of weight gain on birth weight.