Progesterone for Prevention of Miscarriage and Preterm Birth in Women With First-Trimester Bleeding: PREEMPT Trial [A260].

INTRODUCTION: First-trimester bleeding is associated with miscarriage and preterm birth, for which progesterone has been suggested to improve outcomes. Our study objective was to evaluate the effect of progesterone treatment throughout pregnancy on preventing miscarriage and preterm birth in pregnancies with first trimester bleeding. METHODS: This was a multicenter, double-blind, placebo-controlled, randomized trial comparing 200 mg micronized progesterone, vaginally administered nightly from presentation to 34 weeks of gestation, with an identically appearing placebo. Subjects with vaginal bleeding and live intrauterine pregnancy <14 weeks of gestation were eligible. Multifetal gestations, cervical insufficiency, recurrent pregnancy loss, or bleeding unrelated to placentation were excluded. Primary outcome was occurrence of live term pregnancy. Secondary outcomes included adverse maternal/newborn events and time to miscarriage or birth. Chi-square analyses compared proportions and Mann-Whitney tests compared time-to-event outcomes. RESULTS: A total of 549 patients were randomized, of whom 16 withdrew or were lost to follow-up, leaving 264 patients in the progesterone group and 269 patients in the placebo group. Baseline characteristics were comparable in both groups. The number of patients having a live term birth among those in the progesterone group was 197 (74.6%), compared with 190 (70.6%) in the placebo group (P =.30). Compared to the placebo group, those in the progesterone group had comparable risks of abortion <20 weeks (38 (14.4%) versus 43 (16.0%), P =.94), preterm birth (27 [10.2%] versus 33 [12.3%], P =.46), and stillbirth (2 [0.9%] versus 3 [1.3%], P =.65). There were no differences in adverse maternal or newborn outcomes, or in time-to-event for miscarriage or birth between the groups. CONCLUSION: Progesterone prescribed throughout pregnancy is not effective in preventing miscarriage or prematurity in subjects presenting with first-trimester vaginal bleeding in context of a live intrauterine pregnancy. [ABSTRACT FROM AUTHOR]