Optimal Timing of Euploid Day 6 Blastocyst Transfer in Frozen Hormonal Replacement Therapy Cycles: Comparing Day 6 versus Day 7 of Progesterone Administration

What this Trial Is About

Researchers are comparing the timing of transferring euploid day 6 blastocysts in frozen Hormonal Replacement Therapy (HRT) cycles, specifically whether transfer on the 6th or 7th day of progesterone exposure leads to better outcomes in clinical pregnancy, miscarriage, and live birth rates. This study is the first to focus exclusively on euploid day 6 blastocysts to remove the effect of aneuploidy on implantation failure and miscarriage. The timing of progesterone exposure is randomized at the start of progesterone treatment. Participants will receive estradiol valerate starting on day 2 or 3 of menstruation, increasing to a daily dose of 6 mg. Progesterone vaginal suppositories begin when the endometrium shows optimal thickness and a trilaminar appearance, starting with 100 mg doses twice on day 1 and then three times daily from day 2. Embryo transfer is scheduled either on the 6th or 7th full day after starting progesterone. Throughout the HRT cycle, participants undergo transvaginal ultrasounds and blood tests measuring hormone levels, including serum progesterone on the day of embryo transfer. Participants will be monitored with ultrasounds and hormone tests to track endometrial development and hormone levels. The primary outcome measured is live birth rate at 41 weeks. Secondary outcomes include biochemical pregnancy rates, clinical pregnancy rates, ongoing pregnancy rates at 13 weeks, and miscarriage rates at 24 weeks. The study involves careful monitoring to exclude ovarian follicles and assess hormone levels to optimize timing of embryo transfer. Total participation duration is aligned with pregnancy outcomes and follow-up.

Optimal Timing of Euploid Day 6 Blastocyst Transfer in Frozen HRT Cycles, Day 6 or Day 7 of Progesterone Administration.