Personal FET in RIF Patients According to Histological Dating of Endometrial of Natural/ Hormone Replacement Cycle

"According to the histological dating of endometrium of natural/hormone replacement cycle in control group, to explore the effectiveness of intervention by advanced or delayed personal embryo transfer .~The establishment of standard control group: Frozen embryo transfer patients according to the inclusion and exclusion criteria were evaluated for histological dating by endometrial biopsy on 7 days after ovulation/P+7. After routine time transfer in the frozen embryo transfer cycle, the standard of histological dating were determined according to the pregnancy outcome of the FET cycle .~pET in RIF patients was delayed one(ovulation +4/P+4, OV/P+4) / two days(OV/P+3) or advanced one day(OV/P+9). Day 5 blastocysts were transferred with this strategy in natural cycles."