Association of 17α-Hydroxyprogesterone Caproate and Risk of Infection.

OBJECTIVE: To evaluate whether exposure to 17α-hydroxyprogesterone caproate is associated with the rate of peripartum infection in women who deliver preterm and their neonates.

METHODS: This is a retrospective cohort study of patients who delivered before 37 weeks of gestation at a tertiary care hospital between July 1, 2005, and December 31, 2012. Women in the case group (women exposed to 17α-hydroxyprogesterone caproate) were matched to women in a control group (unexposed patients) by gestational age and delivery date. The primary outcome was a composite infection rate comprising histologic or clinical chorioamnionitis, endometritis, or early-onset neonatal sepsis. To detect a 15% difference in composite infection rate between women exposed to 17α-hydroxyprogesterone caproate and those unexposed (two-tailed α=0.05 and power=80%), 183 patients per group were required. Logistic regression was performed to control for a history of prior spontaneous preterm birth and exposure to betamethasone.

RESULTS: The primary outcome frequency for women exposed to 17α-hydroxyprogesterone caproate was 34.6% (64 patients) compared with 33% (61 patients) in those unexposed (P=.74). There was no significant difference between women exposed to 17α-hydroxyprogesterone caproate and those unexposed in frequency of clinical chorioamnionitis (1.9% compared with 1.1%, P=.66), histologic chorioamnionitis (39.4% compared with 40%, P=.92), or early-onset neonatal sepsis (2.7% compared with 1.1%, P=.28). A total of 7.1% of women exposed to 17α-hydroxyprogesterone caproate developed endometritis compared with 2.7% of those unexposed (P=.05). The adjusted odds ratio for the primary outcome in women exposed to 17α-hydroxyprogesterone caproate was 0.65 (95% confidence interval 0.31-1.38).

CONCLUSION: Exposure to 17α-hydroxyprogesterone caproate does not increase the risk of peripartum infection among women who deliver preterm or their neonates.

LEVEL OF EVIDENCE: II.