Immediate Versus Postponed Single Blastocyst Transfer in Programmed or Stimulated Cycle Frozen Embryo Transfer
The aim of this randomized controlled trial is to examine whether single blastocyst transfer in the first cycle after oocyte retrieval (immediate) is non-inferior to single blastocyst transfer in a subsequent cycle (postponed) in stimulated or programmed cycle frozen embryo transfer (FET). The primary outcome is live birth rate.
- EligibilityCriteria: Inclusion Criteria:  Eligible for FET in a programmed- or stimulated cycle immediately following a fresh embryo transfer or freeze all cycle Oligo-anovulatory women (cycle length > 35 days) Ovulatory women (cycle length 21-35 days) At least one vitrified day 5 or 6 blastocyst with Gardner score of ≥ 3BB at the day of vitrification  Exclusion Criteria:  Uterine malformation Presence of hydrosalpinx, submucosal uterine myomas or uterine polyps Allergies or contraindication to standard fertility medication Male or female HIV or Hepatitis B or C Preimplantation genetic testing (PGT) in the fresh cycle Testicular sperm aspiration (TESA) Severe OHSS with hospital admission and ascites drainage during the fresh cycle Oocyte donation - HealthyVolunteers: No - Gender: Female - MinimumAge: 18 Years - MaximumAge: 40 Years - StdAgeList: Adult