LONG ESTRADIOL REPLACEMENT IN AN OOCYTE DONATION PROGRAM

The objective of this study was to optimize, in terms of endometrial r eceptivity (embryo implantation), the limits of unopposed administrati on of oestrogens beyond 35 days in an in-vitro fertilization (IVF) and ovum donation programme, Oocytes donated by 182 women undergoing IVF were distributed among 186 women treated by ovum donation, Five groups of recipients were established according to the duration of oestradio l valerate administration, in a 'prolonged follicular phase' protocol, before embryo replacement, employing oestradiol valerate at increasin g doses up to 6 mg/day, Gonadotrophin-releasing hormone analogues (GnR Ha) were simultaneously administered in ovulatory patients. The dosage of oestradiol valerate was maintained until oocytes were available fo r insemination and subsequent transfer, Donors and recipients were equ ally distributed among groups in terms of age and cause of infertility , There was no difference among groups in serum oestradiol concentrati on the day in which progesterone was added to obtain a secretory trans formation of the endometrium, An analysis of the ovum donation cycles showed no difference among groups in pregnancy and implantation rates after the replacement of a similar number of embryos, Successful impla ntation was observed even after 100 days of unopposed oestradiol valer ate administration, Break-through bleeding increasingly appeared accor ding to the duration of oestrogen replacement, These clinical observat ions provide evidence that the concept of 'prolonged follicular phase' oestrogen replacement for ovum donation can be maintained, at least a s long as 15 weeks, However, because of the high (>44%) incidence of b reak-through bleeding after 9 weeks, it is advisable to stop oestrogen treatment at this point, This protocol enormously facilitates the cha nces of synchronization between donor and recipient in an anonymous oo cyte donation programme.