Oral dydrogesterone versus oral micronized progesterone: Interim analysis of a randomized controlled trial in pregnant women with threatened miscarriage.

BACKGROUND: Progestogen/progestin supplementation is favorable in threatened miscarriage. However, comparative data on the efficacy, safety, and immunomodulatory functions of types/routes of administration are limited. OBJECTIVE: This study compares oral dydrogesterone (DYD) vs. oral micronized progesterone (MP) in threatened miscarriage. MATERIALS AND METHODS: This ongoing, investigator-initiated, randomized controlled trial includes eligible, consenting, pregnant women who had vaginal bleeding and/or abdominal pain during first trimester. Participants are treated up to 14 gestational wk with DYD (40 mg stat followed by 10 mg thrice daily) or MP (200 mg twice daily). The following outcomes till 20 gestational wk are presented: miscarriage rate (primary); change in serum cytokines (interferon gamma [IFN- γ ], tumor necrosis factor alpha [TNF-α], interleukin [IL]-4, IL-10), time to symptom resolution (secondary); treatment-emergent adverse events (AEs; safety). RESULTS: Interim analysis includes 116 participants (DYD, 62; MP, 54). Miscarriage rate in DYD (14.52%) was statistically comparable to, but numerically lower than, that in MP (20.37%; p = 0.558). The mean time to symptom resolution in DYD and MP was, respectively, 6.49 and 7.38 days for vaginal bleeding, and 7.15 and 7.67 days for abdominal pain. Numerically, IFN- γ and TNF-α decreased and IL-4 increased with DYD, while IFN- γ decreased and IL-4 and IL-10 increased with MP. Considering Th1:Th2 ratio, numerical decreases in IFN- γ :IL-4, IFN- γ :IL-10, and TNF-α:IL-4 were evident with DYD but not with MP. No AE was related to study medication. CONCLUSION: Compared to oral MP, oral DYD resulted in a numerically lower miscarriage rate and time to symptom resolution, concomitant to favorable decrease in Th1:Th2 ratio.