Balmaceda, JP; Bernardini, L; Ciuffardi, I; Felix, C; Ord, T; Sueldo, CE; Asch, RH; ,
Although a number of different mechanisms have been suggested to account for the decline of fertility with age, the majority of studies agree that poor oocyte quality and reduced endometrial receptivity are the most important. In fact, the increased incidence of early pregnancy loss and chromosomal abnormalities of oocytes in older women, as well as the ability to reverse decreasing pregnancy rates by using oocyte donation, strongly support the evidence that oocyte ageing is the main factor responsible for decreasing fertility. Conversely, the lack of knowledge of the physiological variables that determine a successful nidation of a human embryo makes the analysis of uterine receptivity much more difficult. In order to evaluate the impact of the age of donors and recipients on pregnancy, implantation and abortion rates, we have retrospectively analysed 258 cycles from our programme of oocyte donation. Results were reviewed according to the following subclasses of age groups: less than or equal to 30, 31-35 and 36-39 years for donors, and less than or equal to 30, 31-35, 36-40, 41-45 and 46-53 years for recipients. For each group of recipients, the average age of the donors, the length of cycle of hormone replacement therapy and the ultrasonographic images of the endometrium were almost identical. Implantation rates achieved with donated oocytes appeared to be negatively associated with the donor age (18.4, 15.5 and 11.4% respectively). The data showed statistical significance by the chi(2) test specifically for donors' age greater than or equal to 36 years. This was not confirmed, however, by logistic regression analysis. Results reported according to the different recipients' age groups were similar for implantation (13, 21 17, 14, and 12% respectively) and abortion (17, 13, 11, 14 and 7% respectively). We conclude that the age of women producing oocytes may affect the chances of embryo implantation, while the women receiving donated oocytes, at least in the range of 30-50 years of age, have equal chances of successful embryo implantation and nidation maintenance.