Preparation of endometrium for egg donation

Nowadays oocyte donation is a well established method of assisted reproduct ion and offers the unique opportunity to treat patients with various clinic al indications, with or without ovarian function. in a novel way. In women with ovarian failure, artificial menstrual cycles are required before proce eding to oocyte donation. Oestrogen may be delivered in the form of oral ta blets, transdermal patches in order to bypass the gastrointestinal tract th us avoiding first pass metabolism and by vaginal application. Our regimen i s oestradiol valerate given in various concentrations, in order to mimic th e regular cyclic fluctuations throughout the cycle. Progesterone may be adm inistered in the form of oral tablets, intravaginal suppositories or rings and i.m. injections. Our results, as of most other groups, strongly support the vaginal route of progesterone administration. In women with retained o varian function, synchronization of donor-recipient cycle presents a specia l problem, as there is strong evidence that a temporal window of maximal en dometrial receptivity exists, Cryopreservation of donated embryos may be us ed to overcome the problem, but this approach has the important drawback of embryonic loss occurring after freezing and thawing. The method of choice is the administration of gonadotrophin-releasing hormone agonists (GnRHa) t o render the patients functionally agonadal in order to circumvent cycle as ynchrony between the donor and recipient.