Spontaneous Preterm Birth in African-American and Caucasian Women Receiving 17α-Hydroxyprogesterone Caproate

ObjectiveTo determine if the rates of recurrent spontaneous preterm birth in women receiving 17-hydroxyprogesterone caproate (17P) differ according to maternal race. Study DesignRetrospective analysis of a cohort of women enrolled in outpatient 17P administration at<27 weeks. Maternal characteristics, obstetric history, and rates of recurrent preterm birth were determined using chi-square and multivariable Cox proportional hazards regression at two-tailed =0.05. Primary study outcome was defined as having a spontaneous preterm birth<34 weeks. ResultsAfrican-American women initiated 17P injections later (19.6 versus 18.9 weeks, p<0.001) and discontinued injections earlier (33.2 versus 34.1 weeks, p<0.001) than Caucasian women. Spontaneous recurrent preterm birth<34 weeks was higher in African-Americans versus Caucasians receiving 17P (odds ratio 2.1; 95% confidence interval 1.7, 2.4). After adjusting for other significant factors, African-American race retained the strongest association with recurrent spontaneous preterm birth<34 weeks. Within each racial group, short cervical length<25mm before 27 weeks' gestation had the highest hazard of recurrent spontaneous preterm delivery. ConclusionDespite treatment with 17P, African-American women have higher rates of recurrent preterm birth.