17-Hydroxyprogesterone Caproate - Safety

Safety

The use of 17-hydroxyprogesterone caproate in pregnancy to prevent preterm birth is not recommended without further study according to two authorities. A 2006 Cochrane Review concluded "...important maternal and infant outcomes have been poorly reported to date... information regarding the potential harms of progesterone therapy to prevent preterm birth is limited". There was a similar conclusion from a review by Marc Keirse of Flinders University. Three clinical studies in singleton pregnancies of 250 mg/week of intramuscular 17-hydroxyprogesterone caproate have all shown a trend for an increase in pregnancy loss due to miscarriage compared to placebo. The FDA expressed concern about miscarriage at the 2006 advisory committee meeting; the committee voted unanimously that further study was needed to evaluate the potential association of 17OHP-C with increased risk of second trimester miscarriage and stillbirth. A toxicology study in rhesus monkeys resulted in the death of all rhesus fetuses exposed to 1 and 10 times the human dose equivalent of 17-hydroxyprogesterone caproate. as of 2008, 17-hydroxyprogesterone caproate is a category D progestin according to the FDA (that is, there is evidence of fetal harm). There is speculation that the castor oil in the 17-hydroxyprogesterone caproate formulation may not be beneficial for pregnancy.