Objective: The aim of this study was to compare the use of micronized vaginal progesterone and oral dydrogesterone in the endometrial preparation for frozen-thawed embryo transfer.
Methods: This was a randomized, controlled, open, two-armed clinical trial, with women undergoing frozen-thawed embryo transfer along with hormone replacement therapy for endometrial preparation, between September 2019 and February 2021. A total of 73 patients were randomly selected and orally administered 40 mg/day dydrogesterone (dydrogesterone group, n=36) or 800 mg/day micronized vaginal progesterone (micronized vaginal progesterone group, n=37), after endometrial preparation with transdermal estradiol. The main outcome was a viable ongoing pregnancy with 12 weeks of gestation as evaluated by ultrasound.
Results: The reproductive outcomes in frozen-thawed embryo transfer cycles were similar, with pregnancy rates in the dydrogesterone and micronized vaginal progesterone treatment groups being, respectively, 33.3 and 32.4% at 12 weeks pregnancy (confidence interval= -22.4-20.6, p=0.196).
Conclusions: The use of oral dydrogesterone may be a more patient-friendly approach to endometrial preparation in frozen-thawed embryo transfer cycles, avoiding undesirable side effects and discomfort resulting from vaginal administration, while also providing similar reproductive results.