BACKGROUNDProgesterone is essential for the maintenance of pregnancy. However, whether progesterone supplementation in the first trimester of pregnancy would increase the rate of live births among women with a history of unexplained recurrent miscarriages is uncertain. METHODSWe conducted a multicenter, double-blind, placebo-controlled, randomized trial to investigate whether treatment with progesterone would increase the rates of live births and newborn survival among women with unexplained recurrent miscarriage. We randomly assigned women with recurrent miscarriages to receive twicedaily vaginal suppositories containing either 400 mg of micronized progesterone or matched placebo from a time soon after a positive urinary pregnancy test (and no later than 6 weeks of gestation) through 12 weeks of gestation. The primary outcome was live birth after 24 weeks of gestation. RESULTSA total of 1568 women were assessed for eligibility, and 836 of these women who conceived naturally within 1 year and remained willing to participate in the trial were randomly assigned to receive either progesterone (404 women) or placebo (432 women). The follow-up rate for the primary outcome was 98.8% (826 of 836 women). In an intention-to-treat analysis, the rate of live births was 65.8% (262 of 398 women) in the progesterone group and 63.3% (271 of 428 women) in the placebo group (relative rate, 1.04; 95% confidence interval [CI], 0.94 to 1.15; rate difference, 2.5 percentage points; 95% CI, −4.0 to 9.0). There were no significant between-group differences in the rate of adverse events. CONCLUSIONSProgesterone therapy in the first trimester of pregnancy did not result in a significantly higher rate of live births among women with a history of unexplained recurrent miscarriages.

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Background and objectivesProgesterone is essential to maintain a healthy pregnancy. Guidance from the Royal College of Obstetricians and Gynaecologists and a Cochrane review called for a definitive trial to test whether or not progesterone therapy in the first trimester could reduce the risk of miscarriage in women with a history of unexplained recurrent miscarriage (RM). The PROMISE trial was conducted to answer this question. A concurrent cost-effectiveness analysis was conducted.Design and settingA randomised, double-blind, placebo-controlled, international multicentre study, with economic evaluation, conducted in hospital settings across the UK (36 sites) and in the Netherlands (nine sites).Participants and interventionsWomen with unexplained RM (three or more first-trimester losses), aged between 18 and 39 years at randomisation, conceiving naturally and giving informed consent, received either micronised progesterone (Utrogestan®, Besins Healthcare) at a dose of 400 mg (two vaginal capsules of 200 mg) or placebo vaginal capsules twice daily, administered vaginally from soon after a positive urinary pregnancy test (and no later than 6 weeks of gestation) until 12 completed weeks of gestation (or earlier if the pregnancy ended before 12 weeks).Main outcome measuresLive birth beyond 24 completed weeks of gestation (primary outcome), clinical pregnancy at 6–8 weeks, ongoing pregnancy at 12 weeks, miscarriage, gestation at delivery, neonatal survival at 28 days of life, congenital abnormalities and resource use.MethodsParticipants were randomised after confirmation of pregnancy. Randomisation was performed online via a secure internet facility. Data were collected on four occasions of outcome assessment after randomisation, up to 28 days after birth.ResultsA total of 1568 participants were screened for eligibility. Of the 836 women randomised between 2010 and 2013, 404 received progesterone and 432 received placebo. The baseline data (age, body mass index, maternal ethnicity, smoking status and parity) of the participants were comparable in the two arms of the trial. The follow-up rate to primary outcome was 826 out of 836 (98.8%). The live birth rate in the progesterone group was 65.8% (262/398) and in the placebo group it was 63.3% (271/428), giving a relative risk of 1.04 (95% confidence interval 0.94 to 1.15;p = 0.45). There was no evidence of a significant difference between the groups for any of the secondary outcomes. Economic analysis suggested a favourable incremental cost-effectiveness ratio for decision-making but wide confidence intervals indicated a high level of uncertainty in the health benefits. Additional sensitivity analysis suggested the probability that progesterone would fall within the National Institute for Health and Care Excellence’s threshold of £20,000–30,000 per quality-adjusted life-year as between 0.7145 and 0.7341.ConclusionsThere is no evidence that first-trimester progesterone therapy improves outcomes in women with a history of unexplained RM.LimitationsThis study did not explore the effect of treatment with other progesterone preparations or treatment during the luteal phase of the menstrual cycle.Future workFuture research could explore the efficacy of progesterone supplementation administered during the luteal phase of the menstrual cycle in women attempting natural conception despite a history of RM.Trial registrationCurrent Controlled Trials ISRCTN92644181; EudraCT 2009-011208-42; Research Ethics Committee 09/H1208/44.FundingThis project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full inHealth Technology Assessment; Vol. 20, No. 41. See the NIHR Journals Library website for further project information.

BACKGROUNDBleeding in early pregnancy is strongly associated with pregnancy loss. Progesterone is essential for the maintenance of pregnancy. Several small trials have suggested that progesterone therapy may improve pregnancy outcomes in women who have bleeding in early pregnancy. METHODSWe conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate progesterone, as compared with placebo, in women with vaginal bleeding in early pregnancy. Women were randomly assigned to receive vaginal suppositories containing either 400 mg of progesterone or matching placebo twice daily, from the time at which they presented with bleeding through 16 weeks of gestation. The primary outcome was the birth of a live-born baby after at least 34 weeks of gestation. The primary analysis was performed in all participants for whom data on the primary outcome were available. A sensitivity analysis of the primary outcome that included all the participants was performed with the use of multiple imputation to account for missing data. RESULTSA total of 4153 women, recruited at 48 hospitals in the United Kingdom, were randomly assigned to receive progesterone (2079 women) or placebo (2074 women). The percentage of women with available data for the primary outcome was 97% (4038 of 4153 women). The incidence of live births after at least 34 weeks of gestation was 75% (1513 of 2025 women) in the progesterone group and 72% (1459 of 2013 women) in the placebo group (relative rate, 1.03; 95% confidence interval [CI], 1.00 to 1.07; P = 0.08). The sensitivity analysis, in which missing primary outcome data were imputed, resulted in a similar finding (relative rate, 1.03; 95% CI, 1.00 to 1.07; P = 0.08). The incidence of adverse events did not differ significantly between the groups. CONCLUSIONSAmong women with bleeding in early pregnancy, progesterone therapy administered during the first trimester did not result in a significantly higher incidence of live births than placebo.