Efficacy of progesterone support for pregnancy in women with recurrent miscarriage. A meta‐analysis of controlled trials

Summary Progesterone appears to be necessary to support an early pregnancy, and it has been used for this purpose for several decades. Its potential role in women with recurrent miscarriage due to luteal phase deficiency has been suggested, but its efficacy has not yet been demonstrated. Three controlled trials of progesterone treatment in women with recurrent miscarriage have shown small, but not statistically significant, increases in the rates of pregnancies that continue beyond 20 weeks in the treated groups. None of these studies had sufficient statistical power to detect a clinically significant improvement in outcome but pooling the results of these studies using the principles of meta‐analysis has allowed an overall effect of treatment to be calculated. The resulting odds ratio for pregnancies reaching at least 20 weeks gestation was 3·09 (95% CI 1·28 to 7·42) which indicates that there is evidence to support the suggestion that progesterone given in early pregnancy is useful in women with recurrent miscarriage. Although, before progesterone is used in this way its efficacy in women with recurrent miscarriage due to luteal phase deficiency must be assessed in prospective double‐blind randomized controlled trials mounted in the light of the results of this meta‐analysis.