What is the most relevant standard of success in assisted reproduction? Singleton live births should also include preterm births.

An intensive debate is ongoing in this journal concerning the most appropriate endpoint after assisted reproduction techniques. The endpoint suggested by the first authors was Birth Emphasizing a Successful Singleton at Term (BESST). We have evaluated the most appropriate endpoint from different perspectives: patients, public, health authorities, obstetric and IVF clinics. We find singleton live birth highly relevant as an outcome parameter as multiple pregnancies are the main factor responsible for the overall poorer obstetric and neonatal outcome in IVF pregnancies, and multiple pregnancies are mostly an avoidable iatrogenic complication. However, our proposal is that both preterm and term singletons should be included since the prematurity rate is an outcome that is largely uninfluenced by the IVF clinics. In conclusion, we propose singleton live birth per cycle initiated as the most appropriate main outcome after assisted reproduction. Prematurity should in addition be reported separately as a secondary outcome.