Improvement of pregnancy and implantation rates in cyclic women undergoing oocyte donation after long-term down-regulation

An oocyte donation programme was carried out in 122 patients aged between 40 and 49 years for a total of 225 replacement cycles. Eggs were donated by 103 women undergoing assisted reproduction technologies in our infertility centre. Recipients were divided into different groups according to whether they were menopausal (group A) or cyclic and treated with short- (group B) or long-term (group C) gonadotrophin-releasing hormone analogues. In group C, the ovarian suppression of the patients was prolonged with the aim of producing a type of artificial menopause. Oocyte donors were aged between 21 and 35 years, and were equally distributed between the different groups. There were significant differences in pregnancy and implantation rates according to ovarian status: 30.8 and 16.1% respectively in group A, 30.6 and 17.7% respectively in group C versus 10.4 and 5.6% respectively in group B. Apart from improved pregnancy and implantation rates in cyclic women aged >40 years after long-term down-regulation, these data seem to demonstrate an important role for the endometrium in the implantation process.