Single embryo transfer

Abstract

Multiple pregnancies present significant problems for mothers and babies. The incidence of twin pregnancies has increased dramatically in the last 30 years, linked to the development of assisted reproductive technologies including in vitro fertilisation (IVF). The occurrence of multiple pregnancies after IVF is directly related to the number of embryos replaced during treatment. Policies to reduce the number of multiple pregnancies through limiting the numbers of embryos transferred have been successfully introduced in some parts of Europe. Anxieties that pregnancy rates would decline significantly after introduction of a policy of single embryo transfer have not been realised, particularly when the pregnancies derived from the transfer of additional cryopreserved embryos are taken into consideration. Obstacles to the introduction of such a policy in the UK relate to the commissioning arrangements for IVF and the competitive commercial environment in which IVF is provided. Continued high multiple pregnancy rates are not acceptable. IVF children should be given the best chance possible of safe delivery, at term, as singletons.