Gonadal activity and chromosomal constitution of in vitro generated embryos

Chromosomal analysis of pre-implantation embryos was carried out in patient s with a poor prognosis of full term pregnancy, which underwent induction o f multiple follicular growth. In all, 1034 embryos generated from 191 stimu lated cycles were screened for nine chromosome aneuploidy by using the mult icolour fluorescence in situ hybridisation technique. Thirty-five percent o f the diagnosed embryos were chromosomally normal, whereas the remaining pr esented with numerical abnormalities, which made them not suitable for tran sfer. The results obtained confirmed that the incidence of abnormalities is mostly dependent on age; however, monosomy and trisomy are more frequent i n poor responders. Accordingly, the pregnancy rate per started cycle was si gnificantly higher in women with a normal response to gonadotropic stimulat ion (33% vs. 8%, P < 0.001). These findings indicate that poor responder pa tients are physiologically exposed not only to reduced chances of implantat ion but also to an increased risk of spontaneous abortion and trisomic preg nancies. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.