ABSTRACT
The first in vitro fertilization (IVF) baby was born as a result of single embryo transfer. As use of IVF increased, there was an increase in use of the number of embryos put back within one treatment. The most important complication of IVF treatment was multiple pregnancies—40% as compared to 2% after spontaneous conception. Single embryo transfer was identified as a way to reduce the multiple pregnancy rate. Although a theoretically sound concept, there were multiple barriers to its implementation, including a perception of reductions in success rates, not being cost effective from some perspectives, not having adequate funding for IVF, and beliefs. As more data are emerging, it is clear that single embryo transfer is and should be the way of the future. This has been facilitated by data suggesting equal pregnancy rates, education programs to raise awareness, better embryo selection tools, improved cryopreservation facilities, and national and international guidance. A lot has been done to promote the use of single embryo transfer, but still a lot needs to be done to match the multiple pregnancy rates subsequent to IVF with those after spontaneous conception.
