Comparison of oral dydrogesterone and vaginal progesterone for luteal phase support in natural and modified natural cycle frozen embryo transfers.

Background: This study evaluates the effectiveness of oral dydrogesterone (DYD) for luteal phase support on pregnancy outcomes in patients undergoing frozen embryo transfer with natural cycle protocols (NC-FET), compared with micronized vaginal progesterone (MVP) and combined therapy.

Methods: A retrospective study analyzed 2,035 NC-FET cycles, including both natural and modified natural cycles, conducted between January 2019 and August 2022. A total of 2,035 NC-FET cycles were analyzed. Participants were categorized into three groups based on luteal phase support regimens: Group A (699 cycles) received oral DYD, Group B (433 cycles) received MVP, and Group C (903 cycles) received combination therapy. The live birth rates and neonatal outcomes were compared among the groups.

Results: The live birth rates were comparable across the groups (43.8%, 39.0%, and 42.1%; P > 0.05). No significant variations were found in clinical pregnancy rate, spontaneous miscarriage rate, ectopic pregnancy rate, premature birth rate, and newborn birth weights. Embryo implantation rates in Groups A and C were significantly higher than in Group B (44.1% and 42.9% vs. 37.8%; P = 0.029). Multi-factor regression analysis identified several independent variables influencing the live birth rate, but luteal support regimens did not significantly impact live birth rates (P > 0.05).

Conclusion: In NC-FET cycles, oral DYD demonstrates clinical efficacy comparable to MVP and combined medication. As a monotherapy, oral DYD expands therapeutic options, offering a convenient and effective choice to improve adherence and achieve similar pregnancy outcomes. This finding is significant for guiding clinical practices towards optimal treatment strategies that prioritize patient compliance and satisfaction.