[Effect of different embryo transfer strategies on the outcome of assisted reproduction]

Currently, there is a rising trend to consider a multiple delivery as a genuine complication of assisted reproduction, which can be prevented by the replacement of one single, selected embryo. Particularly previously infertile women due to their poor reproductive function are at risk of complications during gestation leading to premature delivery. Cerebral palsy is the most common consequence of multiple gestation and a significant cause of disabling among the offspring. Particularly Swedish specialists in reproductive medicine have been at the forefront of the development of single embryo transfer (denominated SET), which has become the main therapeutic strategy in IVF since 2004. In Sweden, approximately 70 % of all treatment cycles with assisted reproduction are now being performed with SET. Despite the transfer of fewer embryos per cycle, acceptable pregnancy rates are being achieved thereby reducing the multiple delivery rate to approximately 5 %. In Switzerland, however, legal restrictions ban the selection of embryos, so that all available embryos (not more than three) are still being transferred.