COMPARISON OF CROWN-RUMP LENGTH MEASUREMENTS USING A REAL-TIME SCANNER IN AN ANTENATAL CLINIC AND A CONVENTIONAL B-SCANNER

In a series of 168 patients in the first trimester of pregnancy, fetal crown‐rump length (CRL) measurements were attempted in the Antenatal Clinic using a linear‐array real‐time ultrasound scanner. The measurements could not be made in 23 of the patients; most of them had a gestational age of less than 10 weeks and the difficulty in obtaining measurements was usually due to an underfilled maternal bladder. When compared with CRL measurements obtained with a conventional B‐scanner, a good correlation was obtained (r = 0·92); 80 per cent of the‘real‐time’values fell within a range of 5 mm of the conventional values. In all patients the estimates of gestational age using the two methods were within one week of each other. Copyright © 1979, Wiley Blackwell. All rights reserved