Implantation: Uterine receptivity in an oocyte donation programme

Oocyte donation is a useful model for the assessment of potentialfactors affecting implantation since embryos generated are fromyounger oocytes than in in-vitro fertilization programmes andare therefore expected to have higher and more consistent implantationrates. Transvaginal sonographic measurement of endometrial thickness,echogenic pattern and uterine artery impedance, measured aspulsatility index (PI) and resistance index (RI), were retrospectivelycompared in 99 recipient women following 117 fresh embryo transfersthat resulted in 51 conception cycles and 66 non-conceptioncycles. The prevalence of a multilayered echogenic pattern wassignificantly greater (91.2%) in conception than in non-conception(44.4%) cycles. No differences in endometrial thickness, PIor RI were observed between conception and non-conception cycles.However, no pregnancy occurred when the PI was 3.4 (sensitivity100%). The number of days or cumulative dose of oestrogen intakeand the serum oestradiol concentration prior to progesteroneadministration were not different in the multilayered patternversus other echogenic pattern groups. The data show that itmay be beneficial to await achievement of a PI < 3.4 anda multilayered pattern endometrium prior to embryo transferin an oocyte donation programme.