ACCURACY OF RADIOLOGICAL ESTIMATES OF GESTATIONAL-AGE USING EARLY FETAL CROWN-RUMP LENGTH MEASUREMENTS BY ULTRASOUND AS A BASIS FOR COMPARISON

Radiological estimates of gestational age in late pregnancy were compared with the gestational ages based on first trimester ultrasound crown‐rump length measurements in a series of 125 patients. It was found that the 95 per cent confidence limits of a radiological estimate were ± 3½ weeks, that both distal femoral and upper tibial epiphyses were frequently present much earlier than 36 and 38 weeks respectively, and that in almost half of the growth‐retarded babies in the series there was a bone‐age discrepancy of three or more weeks. It is recommended that more liberal use is made of early ultrasound measurements for the assessment of gestational age. Copyright © 1979, Wiley Blackwell. All rights reserved