Recipients' age, fresh embryo and blastocyst-stage embryo transfer as favorable factors in a transnational oocyte donation program.

Background: In Italy, egg donation is being allowed again following the ruling by the Constitutional Court N. 162/2014. Nevertheless, the number of voluntary donors is insignificant, probably because no reimbursement is provided. Therefore, the great majority of egg donation cycles are performed by using imported cryopreserved oocytes from foreign countries. However, recent evidence has questioned the overall efficacy of this strategy in comparison with the shipment of frozen sperm and vitrified embryos.

Methods: Retrospective cohort study, conducted at ANDROS Day Surgery Clinic Palermo, Italy in the period 2016-2022, with the objective of evaluating the efficiency of each batch of vitrified oocytes, in terms of completed cycles. The cryopreserved donated oocytes came from a single Spanish clinic (Next Fertility, Valencia, Spain). The primary outcome was the cumulative live birth rate (CLBR). The secondary outcomes were the cumulative ongoing pregnancy rate (COPR), the cumulative clinical pregnancy rate (CCPR) and the miscarriage rate.

Results: The CLBR totaled 35.1%, the COPR 36.8%, the CCPR 49.2% and the miscarriage rate 24.7%. In the multivariate analysis, the probability of success was significantly higher in younger recipients, in fresh embryo transfer and in blastocyst-stage embryo transfer.

Conclusions: Our "transnational" donation program with vitrified oocytes has good success rates. The main focus of our analysis is the negative effect of advancing recipient age on success rates, outlining a possible, important role of age-related uterine factor on implantation mechanisms. This aspect should be emphasized during the counselling with couples much more than is routinely done.