The relationship between maternal birth weight and future reproductive outcome was studied in a cohort of 748 white women with singleton pregnancies. Maternal birth weight was significantly related to stature, prepregnancy weight, pregnancy weight gain, baby's birth weight, gestational duration, relative intrauterine growth, the baby's need for neonatal intensive care, transient tachypnea of the newborn, and idiopathic respiratory distress syndrome. Mothers who weighted 2,000 g or less at birth were at elevated risk for poor pregnancy outcome, although their babies were not smaller than babies of most groups of mothers who weighed more at birth. This suggests that factors interfering with intrauterine growth have an impact on the next generation of babies. In view of the increasing survival of low-birth-weight babies, this possibility bears further investigation.