Avoiding multiple pregnancies in assisted reproductive technologies: transferring one embryo at a time should be the norm.

Multiple pregnancies following fertility treatments typically occur in 30% of women in whom more than one embryo is transferred. Worldwide, fewer than 20 countries have fully funded public fertility treatments, and many women utilizing assisted reproduction technologies are transferring more than one embryo for financial reasons because they consider it will be cheaper to have two embryos transferred in the one procedure. Yet, there is a large body of evidence for the poorer health, economic, and social outcomes for mother and baby from multiple pregnancies. Some countries have reduced the multiple pregnancy rate to less than 5% by linking the funding of ART to policies where the large majority of transfers are single embryos.