Routine blastocyst culture and transfer: 201 patients experience

Purpose: The purpose was to compare the outcomes between day-5 blastocyst and day-2 embryo transfers. Methods: Infertile women who accepted the ovarian hyperstimulation and oocyte retrieval were divided: Group 1, day 2 embryo transfer; group 2, cultured to day 5 in serum-free sequential culture medium and transfer: Early embryo quality and growth, blastocyst formation and quality, implantation rate (IR) and pregnancy rates (PR) were detected. Results: Total blastocyst formation rate was 49.4%. Better early embryo quality (days 2, 3) and higher day 3 blastomere number possess higher blastocyst formation rate. The IR for day 2 and day 5 embryos were 10.8% and 22.2%. respectively. The PR in both groups were comparable (37.3% vs. 41.8%). Conclusions: Blastocyst transfer has higher IR and comparable PR as those of day 2 embryo transfer: Early embryo qualities and day 3 blastomere number are useful in predicting the final blastocyst formation. Blastocyst formation rate is not related to maternal age, infertile causes, insemination methods, and early embryo number.