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Progesterone to prevent miscarriage in women with early pregnancy bleeding: The PRISM RCT

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A. Coomarasamy, H.M. Harb, A.J. Devall, V. Cheed, T.E. Roberts, I. Goranitis, C.B. Ogwulu, H.M. Williams, I.D. Gallos, A. Eapen, J.P. Daniels, A. Ahmed, R. Bender-Atik, K. Bhatia, C. Bottomley, J. Brewin, M. Choudhary, F. Crosfill, S. Deb, W.C. Duncan & 22 more A. Ewer, K. Hinshaw, T. Holland, F. Izzat, J. Johns, M.-A. Lumsden, P. Manda, J.E. Norman, N. Nunes, C.E. Overton, K. Kriedt, S. Quenby, S. Rao, J. Ross, A. Shahid, M. Underwood, N. Vaithilingham, L. Watkins, C. Wykes, A.W. Horne, D. Jurkovic, L.J. Middleton

Original languageEnglish
Pages (from-to)1-70
Number of pages70
JournalHealth Technology Assessment
Issue number33
PublishedJun 2020

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Background: Progesterone is essential for a healthy pregnancy. Several small trials have suggested that progesterone therapy may rescue a pregnancy in women with early pregnancy bleeding, which is a symptom that is strongly associated with miscarriage. Objectives: (1) To assess the effects of vaginal micronised progesterone in women with vaginal bleeding in the first 12 weeks of pregnancy. (2) To evaluate the cost-effectiveness of progesterone in women with early pregnancy bleeding. Design: A multicentre, double-blind, placebo-controlled, randomised trial of progesterone in women with early pregnancy vaginal bleeding. Setting: A total of 48 hospitals in the UK. Participants: Women aged 16–39 years with early pregnancy bleeding. Interventions: Women aged 16–39 years were randomly assigned to receive twice-daily vaginal suppositories containing either 400 mg of progesterone or a matched placebo from presentation to 16 weeks of gestation. Main outcome measures: The primary outcome was live birth at ≥ 34 weeks. In addition, a within-trial cost-effectiveness analysis was conducted from an NHS and NHS/Personal Social Services perspective. Results: A total of 4153 women from 48 hospitals in the UK received either progesterone (n = 2079) or placebo (n = 2074). The follow-up rate for the primary outcome was 97.2% (4038 out of 4153 participants). The live birth rate was 75% (1513 out of 2025 participants) in the progesterone group and 72% (1459 out of 2013 participants) in the placebo group (relative rate 1.03, 95% confidence interval 1.00 to 1.07; p = 0.08). A significant subgroup effect (interaction test p = 0.007) was identified for prespecified subgroups by the number of previous miscarriages: none (74% in the progesterone group vs. 75% in the placebo group; relative rate 0.99, 95% confidence interval 0.95 to 1.04; p = 0.72); one or two (76% in the progesterone group vs. 72% in the placebo group; relative rate 1.05, 95% confidence interval 1.00 to 1.12; p = 0.07); and three or more (72% in the progesterone group vs. 57% in the placebo group; relative rate 1.28, 95% confidence interval 1.08 to 1.51; p = 0.004). A significant post hoc subgroup effect (interaction test p = 0.01) was identified in the subgroup of participants with early pregnancy bleeding and any number of previous miscarriage(s) (75% in the progesterone group vs. 70% in the placebo group; relative rate 1.09, 95% confidence interval 1.03 to 1.15; p = 0.003). There were no significant differences in the rate of adverse events between the groups. The results of the health economics analysis show that progesterone was more costly than placebo (£7655 vs. £7572), with a mean cost difference of £83 (adjusted mean difference £76, 95% confidence interval –£559 to £711) between the two arms. Thus, the incremental cost-effectiveness ratio of progesterone compared with placebo was estimated as £3305 per additional live birth at ≥ 34 weeks of gestation. Conclusions: Progesterone therapy in the first trimester of pregnancy did not result in a significantly higher rate of live births among women with threatened miscarriage overall, but an important subgroup effect was identified. A conclusion on the cost-effectiveness of the PRISM trial would depend on the amount that society is willing to pay to increase the chances of an additional live birth at ≥ 34 weeks. For future work, we plan to conduct an individual participant data meta-analysis using all existing data sets.

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