The customised growth potential: an international research tool to study the epidemiology of fetal growth.

Customised centiles based on individual fetal growth potential enhance our ability to differentiate between physiological and pathological smallness. A series of studies in different maternity populations has found striking similarities in the way fetal growth varies with maternal and pregnancy related characteristics, and has established the clear advantages of this method over generic, population-based birthweight or fetal weight standards. The method opens up many new avenues for the retrospective study of risk factors and fetal growth. The findings quantify the strength of association between fetal growth restriction and perinatal outcome, and therefore also highlight the clinical imperative to improve antenatal detection of the at-risk fetus. Applied prospectively as customised charts, the concept improves the detection of fetal growth restriction and reduces the need for unnecessary investigations.