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Uterine receptivity in an oocyte donation programme.

Oocyte donation is a useful model for the assessment of potential factors affecting implantation since embryos generated are from younger oocytes than in in-vitro fertilization programmes and are therefore expected to have higher and more consistent implantation rates. Transvaginal sonographic measurement of endometrial thickness, echogenic pattern and uterine artery impedance, measured as pulsatility index (PI) and resistance index (RI), were retrospectively compared in 99 recipient women following 117 fresh embryo transfers that resulted in 51 conception cycles and 66 non-conception cycles. The prevalence of a multilayered echogenic pattern was significantly greater (91.2%) in conception than in non-conception (44.4%) cycles. No differences in endometrial thickness, PI or RI were observed between conception and non-conception cycles. However, no pregnancy occurred when the PI was > or = 3.4 (sensitivity 100%). The number of days or cumulative dose of oestrogen intake and the serum oestradiol concentration prior to progesterone administration were not different in the multilayered pattern versus other echogenic pattern groups. The data show that it may be beneficial to await achievement of a PI < 3.4 and a multilayered pattern endometrium prior to embryo transfer in an oocyte donation programme.