Assessing the Convenience of Natural Proliferative Phase Frozen Embryo Transfer
This study will assess the convenience of the natural proliferative phase frozen embryo transfer (NPP-FET) in terms of number of number of appointments needed before cycle scheduling.
- EligibilityCriteria: Inclusion Criteria:  Endometrial thickness ≥ 7 mm on the day of starting progesterone-based luteal phase support (LPS) Serum progesterone levels <1.5 ng/ml on the day of starting progesterone-based LPS LPS with micronized progesterone 400mg b.i.d. Regular cycles (>24 days, ≤ 38 days) IVF/ICSI with donated oocytes Single blastocyst stage embryo transfer First or second embryo transfer from the same cohort  Exclusion Criteria:  Use of exogenous ovarian stimulation during FET Untreated hydrosalpinx, polyp, submucous myomas or severe adenomyosis Recurrent pregnancy loss (≥ 3 previous pregnancy losses) Recurrent implantation failure with embryos from oocyte donation (≥ 3 previous failed embryo transfers) Personalized initiation of exogenous progesterone according to a previous endometrial receptivity assay test - HealthyVolunteers: No - Gender: Female - MinimumAge: 18 Years - MaximumAge: 49 Years - StdAgeList: Adult - StudyPopulation: The study group will include a prospectively recruited cohort of ovulatory patients undergoing their first or second FET attempt following oocyte donation in a natural proliferative phase protocol. The control group will include a retrospective cohort of ovulatory patients undergoing a natural cycle frozen embryo transfer following oocyte donation. - SamplingMethod: Probability Sample