How should we report on perinatal outcome?

Authors should report on neonatal outcome after ART in a well-defined and uniform way, to enable readers to compare the outcome of different studies. For reporting on birthweight, SD scores (z-scores) are to be preferred, customized for the most important physiological variables affecting birthweight, e.g. gestational age, gender of the child and whether it is a singleton or part of a multiple. It may be suggested that ESHRE should support the construction of European customized birthweight tables and make available a software for calculating the z-scores in cohorts.