Gestational age at initiation of 17α-hydroxyprogesterone caproate (17P) and recurrent preterm delivery

Objective. To compare rates of recurrent preterm birth between women starting treatment with 17 alpha-hydroxyprogesterone caproate (17P) at 16 - 20.9 weeks of gestation versus 21 - 26.9 weeks. Methods. Women enrolled in an outpatient program of education, nursing assessment and weekly 17P injections beginning at 16 - 26.9 weeks were eligible. Included were patients with singleton pregnancies and a history of preterm delivery (PTD). Pregnancy outcome was compared between women starting 17P at 16 - 20.9 weeks (n = 156) and those starting 17P at 21 26.9 weeks ( n = 119) using Fisher's exact and Mann - Whitney U test statistics (p < 0.05 considered significant). Results. Mean gestational age at delivery ( 36.8 +/- 3.0 vs. 36.7 +/- 2.5) and rates of PTD at < 37 weeks (40.4% vs. 48.7%), < 35 weeks (16.7% vs. 16.8%) and < 32 weeks (5.1% vs. 5.0%) were similar between the groups; all p > 0.05. Conclusions. Rates of preterm delivery were similar in patients initiating 17P at 16 - 20.9 or 21 - 26.9 weeks. A larger sample size is warranted in order to confirm our findings.