RESUMEN
The selection of pre-embryos for transferred is based on morphological appearance. But some poor quality cleaved embryos also can be cultured to the blastocyst stage and implanted. To assess the clinical pregnancy outcomes of blastocyst transfer which developed from poor quality embryos. A total of 109 cleaved embryos with poor quality were cultured to day 5/day 6 and 27 [24.8%] blastocysts were collected from the 15 cycles/patients undergoing conventional IVF. All the blastocysts were cooling with fast-freezing. Then the blastocysts were warmed for transfer. All of 25 vitrified blastocysts [92.6%] survived after warming and were transferred to 15 patients. Five of the women became pregnant. Our results suggest that vitrified human day 5/day 6 blastocyst transfer which develop from poor quality embryo at day 3 can contribute to increasing cumulative pregnancy rates in assisted reproduction