Luteal start vaginal micronized progesterone improves pregnancy success in women with recurrent pregnancy loss

Objective To assess the effectiveness of luteal start vaginal micronized P in a recurrent pregnancy loss (RPL) cohort. Design Observational cohort study using prospectively collected data. Setting Not applicable. Patient(s) Women seen between 2004 and 2012 with a history of two or more unexplained pregnancy losses 20%) in endometrial glands or empirically despite normal nCyclinE (≤20%). Women with normal nCyclinE (≤20%) who did not receive P were used as controls. Main Outcome Measure(s) Pregnancy success was an ongoing pregnancy >10 weeks in size. Result(s) One hundred sixteen women met the inclusion criteria, of whom 51% (n = 59) had elevated nCyclinE and 49% (n = 57) had normal nCyclinE. Pregnancy success in the 59 women with elevated nCyclinE significantly improved after intervention: 6% (16/255) in prior pregnancies versus 69% (57/83) in subsequent pregnancies. Pregnancy success in subsequent pregnancies was higher in women prescribed vaginal micronized P compared with controls: 68% (86/126) versus 51% (19/37); odds ratio = 2.1 (95% confidence interval, 1.0–4.4). Conclusion(s) In this study, we found that the use of luteal start vaginal micronized P was associated with improved pregnancy success in a strictly defined cohort of women with RPL.