NORMAL FETAL DEVELOPMENT PROFILES - A MOD EL TO OBTAIN STANDARD DEVELOPMENT GRAPHS FOR THE HEAD AND ABDOMINAL PARAMETERS AND THE LONG LIMB BONES

Aim: Age-related and uniformly defined standard graphs were obtained f or the fetal parameters BPD, OFD, HC, ATD, ASD, AC, Fe, Ti, Fi, Hu, Ra and UI. Methods: Data of 2032 healthy pregnant women of sonographical ly confirmed gestational age were used in a prospective cross-sectiona l study to establish reference charts for the fetal head and abdomen a nd the long limb bones. Only patients with an uncomplicated pregnancy were included in the study. The gestational age at which the measureme nts were taken ranged from 12 to 41 completed weeks. All measurements were performed as external-to-external measurements. Results: By means of a mathematical model age related standard reference ranges were ca lculated on the basis of a single formula. Uniformly well-defined stan dard graphs were obtained for all parameters. All fetal parameters sho wed a nonlinear fetal growth. Summary: Contrary to the common methods of creating reference standards by means of high-degree polynomials, t he mathematical model presented here has the advantage of characterisi ng the course of several parameters on the basis of one single formula . This is of great importance for digitising fetal charts in commercia lly available ultrasound machines.