Pregnancy duration with use of 17-α-hydroxyprogesterone caproate in a retrospective cohort at high risk of recurrent preterm birth.

Background: The use of 17-α-hydroxyprogesterone caproate for the prevention of recurrent spontaneous preterm birth has become widespread, yet there are conflicting data regarding its efficacy.

Objective: We sought to determine whether administration of 17-α-hydroxyprogesterone caproate was associated with pregnancy prolongation in women at a high risk of recurrent spontaneous preterm birth.

Study Design: This is a retrospective cohort study of women with singleton pregnancies and a history of spontaneous preterm birth at <37 weeks' gestation who received care at our academic tertiary care center between 2009 and 2019.