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Thoracic Circumference Measurement (Fetal)

Published: August 9, 2026Updated: August 16, 2026

This test measures the size of your baby’s chest at the level of the heart, using ultrasound. It helps monitor fetal growth and development during pregnancy.

Quick summary

["Assesses fetal chest growth for prenatal health monitoring."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
11987-5
Short code
Fet Thorax Circum der US
Synonyms
Fet Thorax Circum der US
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-derived
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test during prenatal ultrasounds to check if your baby’s chest is growing at a healthy rate. It can help identify potential issues with fetal growth or development early on.

How Is the Test Performed?

The test involves an ultrasound scan. A gel is applied to your abdomen, and a transducer is moved gently over your belly to capture images of your baby’s chest. The technician measures the circumference of the chest area around the heart.

What Does the Result Mean?

Results are compared to standard fetal growth charts to determine if your baby’s chest size is within expected ranges. Significant deviations may prompt further evaluation.

What Are the Risks or Side Effects?

There are generally no risks to you or your baby from this ultrasound. Minor discomfort from the gel may occur, but it is temporary.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Fetal Thoracic Circumference

Frequently asked questions

Is this test painful?
No, this test is not painful. You may feel a slight pressure or warmth from the ultrasound probe, but it is generally comfortable.
How often is this test done during pregnancy?
This test is typically performed during routine prenatal ultrasounds, often between the 18th and 24th weeks of pregnancy, but timing can vary based on your healthcare provider’s recommendations.
Can I eat or drink before this test?
No special preparation is needed for this test. You can eat, drink, and move around normally as you would for a regular ultrasound.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy