CrownRumpLänge

Crown-rump length, often abbreviated as CRL, is a measurement taken during pregnancy. It is the distance from the crown of the baby's head to the rump. This measurement is typically obtained through ultrasound imaging. The CRL is a crucial parameter for dating a pregnancy and estimating the gestational age, especially in the first trimester.

The CRL measurement is considered most accurate between 7 and 12 weeks of gestation. As the fetus grows, other measurements become more reliable for determining gestational age, such as the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). The CRL measurement is used to calculate the estimated date of delivery (EDD) with a degree of accuracy. Variations in CRL can sometimes indicate potential developmental issues, although a single measurement out of range does not necessarily mean there is a problem. Follow-up ultrasounds are often recommended if the CRL is significantly different from what is expected for the presumed gestational age. The consistency of CRL growth over successive ultrasounds provides valuable information about fetal development.