After the introduction of new Belgian legislation limiting the number of transferable embryos to prevent multiple pregnancies after assisted reproductive technology, the implantation rate per embryo remained stable at 26% and the clinical pregnancy rate per embryo transfer did not change significantly (37.5% before and 32.5% after legislation), whereas the multiple pregnancy rate per clinical pregnancy decreased threefold from 25.9% to 8.0%) in the Leuven University Fertility Center.