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Prevention of high-order multiple gestations in an in vitro fertilization program.

The aim of this study was to assess the benefits of the transfer of only two of the best quality embryos, three if a woman was over 35 years of age, in terms of pregnancy rate and the incidence of multiple gestations. In 1993-94, when we were replacing three embryos when available and up to five when the woman was over 35 years of age, 217 clinical pregnancies were obtained (25% per embryo transfer). Among them there were 34 (15.6%) twins and 8 (3.7%) triplet pregnancies. Eighty-one patients had surplus embryos cryopreserved. In 1995, with the new policy of transferring only two embryos and three when the woman was over 35 years of age, 170 patients became pregnant (23.9% per embryo transfer). There were 31 (18.2%) twins and no triplet pregnancies. One hundred and forty-four patients had surplus embryos cryopreserved. Although limiting the number of transferred embryos slightly decreases the pregnancy rate, this small reduction can be considered acceptable if the social, health and financial problems associated with high-order multiple gestations are taken into account.