Crown-rump length is a measurement of the fetal length (excluding limbs and the yolk sac). It is measured using an ultrasound up to the 14th week of pregnancy.
CRL is one of the most important ultrasound parameters to date a pregnancy. It may also be used as a correction for gestational age in cases where the menstrual history is unreliable.
If the measurement is abnormally low, the baby may be at risk for chromosomal abnormalities. Multifetal pregnancies typically show higher CRLs than singleton pregnancies, but this group has some variability.
Standard teaching for CRL measurement suggests that an ultrasound image should be obtained of a midline sagittal section of the entire fetus. The fetus should be in a neutral position, and the line connecting the crown and the rump should be approximately 90 degrees from the ultrasound beam.
Using the measurement of crl meaning in pregnancy, a physician can estimate the infant’s gestational age. It is one of the most important scans done during pregnancy.
