Practical considerations with 17-Hydroxyprogesterone caproate for preterm birth prevention: does timing of initiation and compliance matter?

Objectivedetermine whether gestational age of 17-hydroxyprogesterone caproate (17-ohpc) initiation is associated with preterm birth (ptb) risk.study designwe performed a retrospective cohort study using marketscan® data. the primary outcome was ptb < 37 weeks. rates of ptb were compared between medication initiation at 16–21 weeks versus 21–29 weeks. the association between compliance with weekly 17-ohpc injections and preterm birth rate was tested after adjusting for potential confounding variables.resultin all 3374 pregnancies met inclusion criteria. women with an early 17-ohpc start were less likely to deliver preterm than those with a late start (arr 0.88; 95%ci 0.79–0.97; p = 0.02). less compliant patients receiving <25% of recommended doses had a higher ptb rate than those receiving >85% of recommended doses (arr 1.5; 95%ci 1.2–1.7; p < 0.01).conclusionthere is an association between both early 17-ohpc initiation and compliance with reduced rates of ptb.