Are Crl Measurements Accurate?

Measurement of the crown–rump length (CRL) between 6 and 12 weeks is the most accurate dating parameter. CRL measurements of gestational age are accurate to within 3–5 days.

Can CRL measurement be wrong?

Measurement of CRL is the method of choice for ultrasound assessment of gestational age in the first trimester,8 but it is susceptible to intra-observer and inter-observer variation. This may result from inconsistent or incorrect acquisition of the appropriate images.

How accurate is a CRL?

Up to and including 13 6/7 weeks of gestation, gestational age assessment based on measurement of the crown–rump length (CRL) has an accuracy of ±5–7 days 11 12 13 14. Measurements of the CRL are more accurate the earlier in the first trimester that ultrasonography is performed 11 15 16 17 18.