Infertility, defined as the inability to conceive within 1 year of unprotected intercourse1, is estimated to affect as many as 186 million people worldwide2. Reproductive medicine aims to help these couples by offering them the best treatment option.

As individual perception of the effectiveness of any treatment is affected by bias, it is generally accepted that clinical practice should be based on scientific methods. The definition of evidence‐based medicine was first introduced by Sackett as the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients3-5. To achieve this, knowledge should be sought in the medical literature to inform clinical decisions6. Reporting the most relevant and informative outcomes in clinical research, therefore, is mandatory for effective comparison between different interventions6.

In 2003, the European Society for Human Reproduction and Embryology recommended that the outcome measure of assisted reproductive techniques (ART) and non‐ART should be ‘singleton live birth’7. Nothing, however, was stated with respect to the treatment cycle or effectiveness over time. Traditionally, success rates of in‐vitro fertilization (IVF) have been reported in terms of live births per fresh cycle or embryo transfer. However, with the increasing use of embryo freezing and thawing, it is essential that outcomes are reported not only following fresh but also after frozen embryo transfer as a complete measure of success of IVF treatment8. Moreover, evaluations should be extended over treatment strategies that incorporate multiple treatment cycles, even if they are of different types, and should also consider any natural conceptions that occur in between treatments. Here, we advocate that, in both clinical trials and clinical practice, the outcome of fertility treatment should be reported as a function of time and as the outcome of multiple transfers from one cycle or the outcome of multiple cycles in a predefined period.