This study evaluates the effect of treatment with Proluton-Depot (hydroxyprogesterone hexanoate) in early pregnancy, and the final outcome of pregnancy and fetal status. One hundred and fifty patients received intramuscular injection of Proluton-Depot from 6 weeks to 8 weeks to 16 weeks to 18 weeks gestation. The outcome of this treated group was compared with a similar number of 150 patients with similar problems, but the second group received no hormonal treatment. There was no evidence to suggest that Proluton-Depot had any adverse effect on the infant or the final outcome of pregnancy.