What is the most relevant standard of success in assisted reproduction? The singleton, term gestation, live birth rate per cycle initiated: the BESST endpoint for assisted reproduction.

Assisted reproduction programmes do not report success consistently. Rates vary with the definition used. Success must reflect delivery of healthy babies, and the burden of treatment to couples. We report the singleton, term gestation, live birth rate of a baby per assisted reproductive technology cycle initiated for a large IVF programme. We defined assisted reproductive technology cycles as those initiated with the intention of oocyte collection. We examined cycles conducted through Monash IVF in 2001. All women with positive pregnancy tests had first trimester ultrasonography. Obstetric outcomes were recorded. All babies had neonatal examinations conducted by paediatricians. A total of 644 positive pregnancy tests were recorded in 2600 cycles; 509 showed fetal heart motion. Of 448 deliveries, 328 were singleton and 120 were multiple. There were 290 singleton deliveries at term gestation. In 2001, a couple had an 11.1% chance of delivering a singleton, term gestation, live baby per assisted reproductive technology cycle begun. We suggest that delivery of a single, term gestation, live baby per cycle initiated is the most relevant standard of success. This statistic was 11.1% at Monash IVF. We encourage programmes to report this BESST (Birth Emphasizing a Successful Singleton at Term) outcome.