Transferring more than 1 embryo simultaneously is justifiable in most patients

Abstract Elective single embryo transfer (eSET), first introduced to in vitro fertilization (IVF) in 1999, is one of the most consequential changes introduced. It can be viewed as the first (among many since) “add-ons” to IVF that has significantly and adversely affected how IVF is practiced, resulting in astonishing declines in live birth rates following fresh non-donor IVF cycles around the world. We offer that, like most “add-ons” to IVF over recent years, the almost universal use of eSET worldwide not only lacks proper validation of its underlying hypothesis, but is based on statistically incorrect assumptions and incorrect data interpretation. As eSET, like most other recent “add-ons” to IVF, lacks evidentiary support, its remarkable success in the marketplace must be based on expert opinions, the lowest level of evidence in medicine and widely recognized as frequently biased. Like other “add-ons” to IVF, eSET-practice, therefore, must be reassessed since it, not only does not offer the benefits it has been widely claimed to provide, but prolongs time to conception and adversely affects live birth chances for many women. Moreover, by ignoring that infertile women value quick conception over most other considerations, provider-insistence on eSET frequently deprives them of the right to self-determination.