Efficacy of 17alpha-hydroxyprogesterone caproate in the prevention of premature labor

We conducted a double-blind study to determine the efficacy of 17alpha-hydroxyprogesterone caproate in preventing premature delivery in 43 high-risk patients. Premature delivery did not occur in 18 patients receiving the progestational agent, whereas 41 per cent of the 22 receiving the palcebo had premature delivery (P less than 0.01). The mean duration of pregnancy and the mean birth weight in the former group (38.6 weeks +/- 1.6 S.D., and 2836 g +/- 412 S.D.) were both significantly greater (P less than 0.025) than that in the latter (35.2 weeks +/- 6.7 S.D.; 2361 g +/- 1085 S.D.). The perinatal mortality rate in the group given the progestational agent (O per cent) was significantly less than that observed in the placebo group (27 per cent) (P less than 0.05). Although there were no complications attributable to the progestational drug, the study population was too small for assessment of immediate or long term safety. However, the results indicate a possible obstetric use for this drug.