@article{3048678, title = "Pregnancy results after ovum donation following one to seven embryo transfers", author = "Mantzavinos, T and Rizos, D and Dimitriadou, F and Arvaniti, K and and Kanakas, N and Voutsina, K", journal = "Fertility and Sterility", year = "1996", volume = "66", number = "5", pages = "765-768", publisher = "AMER SOC REPRODUCTIVE MEDICINE", issn = "0015-0282, 1556-5653", doi = "10.1016/S0015-0282(16)58633-6", keywords = "oocyte donation; repeated embryo transfers; embryo quality; endometrial lining", abstract = "Objective: To determine whether failure to achieve pregnancy after repeated ET after ovum donation was due to an endometrial defect or to the embryo quality. Design: Retrospective data analysis. Setting: A private infertility center. Patient(s): Four hundred sixty-seven donors (513 cycles) undergoing IVF donating oocytes to 266 recipients (423 cycles). Intervention(s): Hormonal endometrial preparation with increasing dosages of valerate E(2) (2, 4, and 6 mg) and 100 mg of P. Main Outcome Measure(s): Pregnancy rates (PRs) and abortion rates in patients undergoing one to seven ETs after ovum donation. Result(s): Pregnancy rates in recipients that had one or two ETs were significantly higher (34.8%) compared with those of recipients having three or more ETs (15.1%). Abortion rates were significantly higher (54.5%) in recipients repeating more than three ETs than in the recipients having one or two ETs (29.1%). Conclusion(s): Recipients that had failed to establish a pregnancy after two ETs had a lower PR in successive attempts, possibly because of a defect of their endometrial lining." }