Retnakaran R, et al. - This research was performed in order to examine the correlations of directly measured maternal pregravid weight and the timing of subsequent weight gain across pregnancy with infant birth weight. The determinant of infant birth weight was disclosed to be the maternal weight, only in the first half of gestation. Based on the results, it was determined that before pregnancy and early gestation could serve as a critical window for intervention to exert an impact on the subsequent birth weight.