Progesterone therapy for prevention of recurrent spontaneous preterm birth in a minority patient population: a retrospective study

TL;DR

This study examines whether progesterone treatments can prevent early births in high-risk minority patients, but finds no significant benefit.

Contribution

The study evaluates progesterone therapy's effectiveness in a minority population for preventing recurrent preterm births, revealing no significant risk reduction.

Findings

Neither intramuscular 17-OHPC nor vaginal progesterone significantly reduced recurrent spontaneous preterm birth before 37 weeks.

Among patients with a short cervix, intramuscular 17-OHPC was associated with increased risk of preterm birth before 37 weeks.

Vaginal progesterone showed no significant association with preventing preterm birth at any gestational age.

Abstract

Preterm birth is a leading cause of infant morbidity and mortality worldwide. The burden of prematurity underscores the need for effective risk reduction strategies. The purpose of this study is to evaluate the efficacy of progesterone therapy, both intramuscular 17-α-hydroxyprogesterone caproate (IM 17-OHPC) and vaginal progesterone, in the prevention of recurrent spontaneous preterm birth (sPTB). The co-primary outcomes included: recurrent spontaneous PTB < 37 and < 34 weeks’ gestation.

This retrospective cohort study included 637 pregnant patients that delivered at any of the three hospitals within the Los Angeles County healthcare system between October 2015 and June 2021. We compared frequencies of measured variables between each of the progesterone treated groups to no treatment using Pearson chi-squared tests and independent t-tests for categorical and continuous variables, respectively. We estimated crude and adjusted associations between each specific treatment (versus no treatment) and primary outcomes using logistic regression.

Recurrent sPTB < 37 weeks’ gestation occurred in 22.3% (n = 64) of those in the no treatment group, 29.1% (n = 86, p = .077) in the 17-OHPC group, and 14.3% (n = 6, p = 0.325) in the vaginal progesterone group. Recurrent sPTB < 34 weeks’ gestation was 6.6% (n = 19) in the no treatment group, 11.8% (n = 35, p = .043) in the 17-OHPC group, and 7.1% (n = 3, p = 1) in the vaginal progesterone group. Among all participants, neither 17-OHPC nor vaginal progesterone was significantly associated with a reduction in recurrent sPTB at any time point. Among those with a short cervix, IM 17-OHPC was positively associated with recurrent sPTB < 37 weeks’ gestation (aOR 5.61; 95% CI 1.16, 42.9).

Progesterone therapy of any type did not reduce the risk of recurrent sPTB < 34 or < 37 weeks’ gestation compared to no progesterone therapy.

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