Quality of first-trimester measurement of crown-rump length.

OBJECTIVE

The purpose of this study was to evaluate the quality of crown-rump length (CRL) measurements in scans judged to be of high quality for the measurement of the nuchal translucency.

STUDY DESIGN

We analyzed prospective data on 68,250 scans by 1913 sonographers that were collected by the French College of Fetal Echography (CFEF) national practice assessment program for the first-trimester scan. The scans were evaluated according to the CFEF image scoring method (CFEF-ISM), which includes items to measure the quality of the scan for both nuchal translucency and the CRL measurements. The scans were classified into 4 quality groups with the use of the full CFEF-ISM score and then a shortened version of the CFEF-ISM that excluded the item on quality of CRL measurement. The proportion of scans with an inaccurate CRL measurement was compared across the different quality groups.

RESULTS

Overall, 21.67% of scans were of insufficient quality for CRL measurement. Among 23,764 "excellent" scans according to the full CFEF-ISM, 965 scans (4.06%) had insufficient CRL quality vs 9.24% of scans with "excellent" quality on the short CFEF-ISM (relative risk, 2.27; 95% confidence interval, 2.11-2.44; P < .001).

CONCLUSION

High scores of the quality of nuchal translucency measurement do not guarantee accurate measurement of crown-rump length. Specific measures are needed to evaluate and to improve the quality of the measurement of crown-lump length.