The goal of an IVF cycle is the birth of at least one baby per intention to treat. However, IVF cannot confer competence on an embryo, but only can provide each couple with a safe treatment to meet a predetermined chance of success. This commentary highlights how clinical, financial and patient-centred perspectives should be included in the definition of success in IVF. The primary outcome, which is the cumulative live birth delivery rate per intention to treat, must always be complemented by analyses of risks, costs and time invested, as well as by measures of patient satisfaction. Finally, it is essential, whenever clinical conditions exist, to limit treatment discontinuation after failed attempts. Constant monitoring of the data is pivotal and must be adjusted for patient characteristics and compared with national and international registers. The authors aimed to review all these aspects and highlight the points that are still open for discussion. Is it time for a consensus?

Traditionally, IVF success rates have been reported in terms of live birth per fresh cycle or embryo transfer. With the increasing use of embryo freezing and thawing it is essential that we report not only outcomes following fresh but also those after frozen embryo transfer as a complete measure of success of an IVF treatment. Most people agree that an individual\'s chance of having a baby following fresh and frozen embryo transfer should be described as cumulative live birth rate. However, views on the most appropriate parameters required to calculate such an outcome have been inconsistent. There is an additional dimension-time for all frozen embryos to be used up by a couple, which can influence the outcome. Given that cumulative live birth rate is generally perceived to be the preferred reporting system in IVF, it is time to have an international consensus on how this statistic is calculated, reported and interpreted by stakeholders across the world.