Individualized growth assessment: evaluation of growth using each fetus as its own control.

In Individualized Growth Assessment, each fetus serves as its own control. Rossavik growth models [P = c[t](k + s[t])] for the 5 anatomical parameters of the Prenatal Growth Profile are specified from 2nd trimester measurements obtained from a given fetus. These growth models are used to determine expected 3rd trimester growth trajectories and to predict birth characteristics. Actual measurements obtained in the 3rd trimester and at birth are compared to expected measurements by calculation of Percent Deviation and Growth Potential Realization Index values, parameters proportional to the difference between measured and expected average growth rates in the 3rd trimester. Prenatal Growth Assessment Scores and modified Neonatal Growth Assessment Scores, calculated from Percent Deviation and Growth Potential Realization Index values for the 5 anatomical parameters, respectively, can be used to detect growth abnormalities manifesting themselves differently in different individuals. Individualized Growth Assessment methods have effectively identified growth abnormalities in fetuses and neonates except in prenatal cases where only a change in soft tissue has occurred.