Journal of Ultrasound in Medicine, Vol 10, Issue 10 557-561, Copyright © 1991 by American Institute of Ultrasound in Medicine
How accurate is second trimester fetal dating?
F. P. Hadlock, R. B. Harrist and J. Martinez-Poyer
Department of Radiology, Baylor College of Medicine, Houston, Texas 77030.
In this study, the Hadlock models for fetal dating using single and
multiple parameters were tested retrospectively in 1770 chromosomally
normal singleton fetuses in the second trimester (14 to 21 weeks of fetal
development). The 95% confidence interval using measurements of the fetal
head and femur individually was approximately +/- 1 week, which is
comparable to the results of recently published dating models from other
centers designed specifically for use during this time frame. The use of
multiple-parameter models results in statistically significant improvement
in prediction of age, in terms of both random error and maximum observed
errors. We conclude that these models, developed for dating between 14 and
42 weeks of fetal development, provide highly accurate estimates of fetal
age in the second trimester of pregnancy.
