Impact of prior gestational age at preterm delivery on effectiveness of 17-alpha-hydroxyprogesterone caproate in practice

Objective We sought to examine if 17-alpha-hydroxyprogesterone caproate (17OHPC) effectiveness is dependent on the earliest gestational age (GA) at prior spontaneous preterm birth (SPTB) when administered in the clinical setting. Study Design Women enrolled for outpatient services with current singleton gestation and ≥1 prior SPTB between 20-36.9 weeks were identified. Data were divided into 3 groups according to earliest GA of prior SPTB (20-27.9, 28-33.9, and 34-36.9 weeks). We compared GA at delivery of current pregnancy and incidence of recurrent SPTB between women enrolled in outpatient 17OHPC administration program (n = 2978) and women receiving other outpatient services without 17OHPC (n = 1260). Results Rates of recurrent SPTB for those with and without 17OHPC prophylaxis, respectively, according to GA at earliest SPTB were: 20-27.9 weeks at earliest SPTB, 32.2% vs 40.7%, P = .025; 28-33.9 weeks at earliest SPTB, 34.1% vs 45.5%, P P Conclusion 17OHPC given to prevent recurrent SPTB is effective regardless of GA at earliest SPTB.