Prevention of Recurrent Preterm Delivery by 17 Alpha-Hydroxyprogesterone Caproate

Abstract

to the editor: After reading the article by Meis et al. (June 12 issue), 1 we strongly discourage practitioners from using 17 alpha-hydroxyprogesterone caproate in the care of women who have had preterm deliveries, until more investigation is done. Although initially enthusiastic about the results, which showed a risk reduction among the women who received 17 alpha-hydroxyprogesterone caproate, we were concerned about the high rate of recurrent preterm delivery among the women who received placebo. The Methods section states that the placebo was castor oil. Ricinoleic acid, the active ingredient in castor oil, is a known uterine stimulant. 2,3 Castor oil is used to induce labor. 4 We speculate that the high rate of preterm delivery in the placebo group was due to the injections of castor oil. If the study medication was given in castor oil (the authors do not say whether it was), then any beneficial effect may have been negated by the vehicle. If not, then the rate of preterm delivery among those receiving 17 alpha-hydroxyprogesterone caproate was no better than that in the historical controls. 5