CRL
Pronunciation: see-ar-el
Also written as: CRL — Crown-Rump Length
Crown-rump length, ultrasound measurement from fetal head to buttocks used for gestational age dating in early pregnancy.
Full Definition
Crown-rump length (CRL) is the standard ultrasound measurement used for gestational age determination in the first trimester of pregnancy. The measurement extends from the top of the fetal head (crown) to the bottom of the torso (rump), excluding the limbs. CRL is most accurate for dating between 7-14 weeks of gestation, with accuracy within ±3-5 days when properly obtained. This measurement is preferred over last menstrual period dating when there is a discrepancy of more than 7 days. CRL growth follows predictable patterns, and significant deviations may indicate chromosomal abnormalities or early pregnancy complications. Proper measurement technique requires sagittal view with neutral fetal flexion.
Usage
Usage note: Hyphenate when spelled out; most accurate dating parameter in first trimester.
In Context
- "CRL measurement of 45mm corresponded to 10 weeks 3 days gestational age." — First trimester ultrasound
- "Dating was revised based on CRL measurement showing 8-day discrepancy from LMP." — Gestational age assessment