HomePregnancyCrown Rump Length (CRL) Chart: Ultrasound Report

Crown Rump Length (CRL) Chart: Ultrasound Report


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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 in pregnancy, a physician can estimate the infant’s gestational age. It is one of the most important scans done during pregnancy.

If you want to know more about crown rump length (CRL) chart ultrasound report, continue reading. 

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CRL Meaning In Pregnancy

Crown Rump Length is measured at the crown of the head of the developing fetus. It relates to gestational age and is used to date pregnancy. It is a measurement borrowed from early 20th-century embryologists. They noticed that preserved specimens of early miscarriages assumed a sitting position. The term “crown rump length” was therefore coined.

Crown-rump length is an ultrasound measurement that measures the length of the fetus or embryo at early gestation. It is not accurate for measuring the yolk sac or limbs but is useful for determining gestational age. The measurement can be taken from around six to seven weeks into a pregnancy and can be used to estimate gestational age up to 14 weeks. The measurement is highly reproducible, making it a valuable tool in the early stages of pregnancy.

The Crown Rump Length (CRL) is measured in ultrasound at the first prenatal visit. It can help determine gestational age and fetal aneuploidy status. It may also help detect a malfunctioning placenta.

What Is Fetal Ultrasound Measurement?

Fetal ultrasound measurements are an important part of a prenatal exam. They help physicians establish a fetus’s gestational age and may indicate various conditions. These measurements may include a fetus’s AP and transverse diameters.

Fetal ultrasound measurements have been used for at least four decades in obstetrics. Increasingly, they are being used to guide the clinical management of pregnancies. This information is important in identifying pathological changes and making informed decisions regarding the child’s health and safety. 

Fetal ultrasound measurements can be expressed as raw data or in percentage deviations from the median. These measurements change over gestation. Moreover, they can be reported using centiles, Z-scores, and multiples of the median. The fetal ultrasound measurements are important for prenatal care. 

What Is CRL In Pregnancy?

Crown-rump length is an important part of your pregnancy health. It measures the embryo’s length and correlates with the fetal heart rate. The crown-rump length of your pregnancy can help determine your gestational age. 

This is different from your fertilization age, usually around two weeks earlier. The ultrasound can also help detect the heartbeat of your fetus. During your pregnancy, your doctor will be able to determine the length of your crown rump with your ultrasound scan.

The CRL is the most important parameter in ultrasounds for dating your pregnancy. It also has the potential to correct gestational age in cases of unreliable menstrual history. The best way to know your CRL is to have your ultrasound during the first trimester.

What Is Crown Lump Length Chart?

A crown lump length (CRL) chart is a useful tool for determining the gestational age of a pregnant woman. This measurement measures the distance from the top of the head to the buttocks of the fetus or embryo. It is used to determine the gestational age of a pregnant woman in the early stages of her pregnancy. 

Ideally, the CRL should be taken in relation to the date of your last menstrual period. In addition, the chart should be performed on a woman who has not been using the pill or breastfeeding in the previous two months.

The crown-rump length is measured during pregnancy and is a vital part of antenatal care. A reliable estimate of gestational age helps doctors monitor the fetus and identify complications. It also helps them monitor the fetus’s growth and heart rate.

What Is Fetal Crown Rump Length?

The fetal crown-rump length is a measurement of the fetus’s head circumference, excluding the yolk sac and limbs. The measurement is usually taken at the earliest point in pregnancy and is accurate up to about 14 weeks of gestation. 

An ultrasound can be used to determine the fetal crown-rump length. There is no international standard for this measurement, but a recent project sought to develop the first international standards for ultrasound dating of pregnancy.

To determine the gestational age of a fetus, two measurements are used – the gestational sac mean diameter and the fetal crown-rump length. Each measurement measures a different aspect of the first trimester. Measurements are usually made between small and larger crosses on a transverse image.

What Are the Uses of Crown Rump Length Measurement?

Crown-rump length measurement is highly accurate for estimating gestational age in early pregnancy. It excludes the yolk sac and extremities. It is usually taken during the sixth to the thirteenth week of pregnancy. In addition, the measurement is used to assess fetal growth.

This measurement is useful in the diagnosis of growth restriction. The ideal CRL is between 45 and 84 mm. This measurement is also important for identifying twins. Twins can be diagnosed at an early stage in pregnancy. Multiple gestations can also be determined when two fetal poles are present in one gestational sac.

Measurement of crown-rump length is a crucial part of routine antenatal care. It allows for accurate gestational age estimation and can guide prenatal testing, growth assessment, and delivery timing. It is also important to interpret the variables used in prenatal screening.

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What Does Crown Rump Length Indicate About Your Baby’s Health?

Crown-rump length is a measurement that is taken by ultrasound during pregnancy. This measurement is in centimetres, and refers to the length of the baby from the top of its head to the bottom of its buttocks, excluding the yolk sac and limbs. Here are some things crown rump length indicates about your baby’s health

  • Presence Of A Heartbeat
    The presence of a heartbeat in the embryo is a reliable indicator of pregnancy. If the CRL is 7mm or more, the ultrasound will help you check the fetus’s heartbeat. This type of ultrasound is done through the vagina instead of outside. When estimating gestational age, the length of the crown-rump length is considered to be an important indicator of fetal development. This measurement can improve the accuracy of measuring gestational age. 
  • Miscarriage

During early pregnancy, your doctor may measure your baby’s crown-rump length. This measurement helps to determine the health status of the developing embryo. If the length is smaller than you expected, your pregnancy might be on its way to miscarriage. If the length is longer than expected, your pregnancy could be healthy. Crown-rump length (CRL) is a measurement of the fetus or embryo’s top-to-bottom length. 


  • What Is CRL Full Form In Pregnancy?

The full form of CRL in pregnancy is crown-rump length. It is an important measurement in pregnancy. It measures the length of a fetus’ crown from top to bottom and is considered the most accurate measurement of gestational age during early pregnancy. 

  • Is CRL Smaller For Girls?

When calculating fetal gender, crown-rump length (CRL) is a key factor. During the early first trimester, male fetuses are larger than female fetuses. This fact has been well documented in the pediatric literature.

  • What Is A Normal CRL At 8 Weeks?

If you’re pregnant, your CRL at eight weeks will be 15mm. This is the normal range of CRL at 8 weeks. 


CRL in pregnancy is a common measurement used by doctors to estimate gestational age. It is often used in conjunction with LMP to determine how many weeks the baby is growing. Using the CRL to estimate gestational age can help parents prepare for premature delivery. CRL is the most important ultrasound parameter to date a pregnancy. It can also be used to correct gestational age in cases of unreliable menstrual history. If you are pregnant, you need to go for an ultrasound to check the crown-rump length. 

Srujana Mohanty
She is the Managing Editor of Cogito137, one of India’s leading student-run science communication magazines. She's been working in scientific and medical writing and editing since 2018, also associated with the quality assurance team of scientific journal editing. Majored in Chemistry with a minor in Biology at IISER Kolkata, Srujana loves doodling and watching series.


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