[Normal fetal growth profile--a uniform model for calculating normal curves for current head and abdomen parameters and long limb bones].

AIM

Age-related and uniformly defined standard graphs were obtained for the fetal parameters BPD, OFD, HC, ATD, ASD, AC, Fe, Ti, Fi, Hu, Ra and Ul.

METHODS

Data of 2032 healthy pregnant women of sonographically confirmed gestational age were used in a prospective cross-sectional study to establish reference charts for the fetal head and abdomen and the long limb bones. Only patients with an uncomplicated pregnancy were included in the study. The gestational age at which the measurements 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 calculated on the basis of a single formula. Uniformly well-defined standard graphs were obtained for all parameters. All fetal parameters showed a nonlinear fetal growth.

SUMMARY

Contrary to the common methods of creating reference standards by means of high-degree polynomials, the mathematical model presented here has the advantage of characterising the course of several parameters on the basis of one single formula. This is of great importance for digitising fetal charts in commercially available ultrasound machines.