Data from a large prospective study were analyzed to determine if taking dextroamphetamine during pregnancy affects fetal growth or fetal/neonatal mortality. 237/42,101 women took the drug to control weight gain. Birth weights were not significantly affected when the drug was discontinued before the 28th week of gestation, but after the 28th week birth weights were 4% lower (144 g) when the drug had been taken in high weight gain gestations (p less than 0.01). The body lengths and head circumferences of neonates were not affected. The perinatal mortality rate was 38/1,000 births for both offspring of drug users and nonusers.