Natural Cycle vs Programmed Cycle Frozen Embryo Transfer

The goal of this[ type of study: randomized controlled trial]is to compare Preeclampsia following Natural vs. Artificial Cycle in patients undergoing frozen embryo transfer.The main question[s] it aims to answer is• Does NC-FET decreases the incidence of preeclampsia in patients undergoing frozen embryo transfer as compared to AC-FET ?The main objective is to compare the proportion of preeclampsia in women with a viable pregnancy with natural cycle protocol to artificial cycle protocol when practicing frozen embryo transfer. Participants recruited will be divided into two ARM(1513 per arm). ARM 1 will undergo the Natural Cycle procedure of Embryo transfer, and ARM 2 will undergo the Artificial Cycle procedure of Embryo transfer. The primary outcome will be the proportion of preeclampsia. The duration of the study is around 2 year.

Inclusion Criteria:Endometrial preparation with Hormone replacement therapy/ Natural cycle.Age 21-45 years following an autologous IVF cycle (with or without preimplantation genetic testing for aneuploidy)BMI > 18 and < 30 kg/m2Endometrial thickness ≥ 7 mm after estrogen therapy or on the day of ovulationBlastocyst embryo transferExclusion Criteria:Uterine diseases (e.g. submucosal fibroids, polyps, previously diagnosed Müllerian abnormalities)Hydrosalpinx untreated.Recurrent pregnancy loss (≥ 3 previous miscarriages)Recurrent implantation failure (≥ 3 previously failed embryo transfers of good-quality blastocysts)Allergy to study medicationPregnancy or lactation at recruitmentContraindications for hormonal treatment