Should we customize fetal growth standards?

Several maternal and fetal physiological characteristics account for a substantial proportion of the variation in birth weight. These characteristics can be used to calculate an individualized optimal birth weight and to adjust or 'customize' the birth weight standard. Customized birth weight standards improve the distinction between constitutional and pathological smallness, and there is evidence that this finding can be extrapolated into the fetal period to evaluate intrauterine growth, but further studies are required to evaluate and quantify the effectiveness of customized versus conventional charts in improving the diagnosis of pathological smallness before birth.