Journal of Ultrasound in Medicine, Vol 4, Issue 6 287-292, Copyright © 1985 by American Institute of Ultrasound in Medicine
Ultrasound fetal thigh-calf circumferences and gestational age--independent fetal ratios in normal pregnancy
A. M. Vintzileos, S. Neckles, W. A. Campbell, B. M. Kaplan, J. W. Andreoli Jr and D. J. Nochimson
The growth of the sonographically measured fetal thigh and fetal calf
circumferences was studied during normal pregnancy. The normal range of
fetal thigh and fetal calf circumferences for each week of pregnancy was
determined from 20 to 41 weeks. The ratios of the ultrasonically measured
fetal femur length to thigh circumference (expressed as femur length/thigh
circumference X 100) and fetal tibia length to calf circumference
(expressed as tibia length/calf circumference X 100) were also determined.
These ratios were found to be relatively constant, with normal ranges after
20 weeks of 51.8 +/- 7.8 and 57.6 +/- 9.4 (mean +/- 2SD) respectively. The
applications of these new fetal parameters in the evaluation of abnormal
fetal growth patterns are discussed. It is suggested that these ratios
should be used in evaluating fetal growth in high-risk patients who present
late in pregnancy with unknown dates.
