Endometrial injury, the quality of embryos, and blastocyst transfer are the most important prognostic factors for in vitro fertilization success after previous repeated unsuccessful attempts

Purpose The purpose of this study was to find out the most important prognostic factors for achieving a pregnancy after in vitro fertilization (IVF) in women with history of repeated unsuccessful IVF attempts. Methods We analyzed factors affecting pregnancy rate in a retrospective study including 429 IVF/ICSI cycles performed in women younger than 40 years with at least three previous consecutive failed IVF/ICSI attempts. Results Clinical pregnancy was observed in 140/429 (32.6%) cycles. Clinical pregnancy rate (CPR) was significantly higher in cycles with LEI compared to cycles without LEI before embryo transfer (44.4 vs 26.54%, p = 0.007). The CPR was also higher in cycles with day 5 blastocyst- compared with day 3 cleavage-stage embryo transfers (45.51 vs 26.54%, p