Radiology, Vol 122, 781-786, Copyright © 1977 by Radiological Society of North America
A composite curve of ultrasonic biparietal diameters for estimating gestational age
SN Wiener, MJ Flynn, AW Kennedy and F Bonk
A composite curve of biparietal diameters at various gestational ages was
constructed from previous reports from five large centers. Estimates of the
mean gestational age using the composite curve compared favorably with
other reporting institutions. This suggests that the newly established
echography department may employ the composite curve of mean values and
need not develop its own biparietal growth curve. The clinical application
of these mean values however, should recognize a considerable variance from
the mean. These variations represent normal growth differences in the
biparietal dimension, errors inherent in the ultrasonic methodology and
apparent differences in the populations examined. A method is suggested by
which variations from the mean may be identified for each echographic
facility.
