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Fetal Thoracic Area Measurement (Ultrasound)

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

This test measures the size of your baby’s thoracic (chest) area during pregnancy using ultrasound. It helps assess whether the baby’s chest appears normal in size and shape.

Quick summary

["This test helps monitor fetal development and detect potential issues early."]

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

Key facts at a glance

LOINC
33068-8
Short code
Fet Thoracic area US.meas
Synonyms
Fet Thoracic area US.meas
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-measured
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

What This Test Measures

An ultrasound technician uses sound waves to create images of your baby’s chest. The test focuses on the thoracic area, measuring the distance around the chest to evaluate its size relative to expected growth patterns.

Why It’s Done During Pregnancy

Your healthcare provider may order this test if you’re at higher risk for certain conditions (e.g., congenital heart defects) or if your baby’s growth appears slower than expected. It’s also used in routine prenatal care to track development.

How the Test Works

You’ll lie on an exam table while a gel is applied to your abdomen. A transducer (probe) is placed on your skin to send and receive sound waves. The images captured help measure the thoracic circumference and compare it to standard fetal growth charts.

What to Expect Before the Test

No special preparation is needed. Wear comfortable clothing and avoid applying lotions or creams on your abdomen the day of the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal measurements may signal potential issues like fetal growth restriction, congenital heart defects, or other structural concerns. Early detection allows for timely medical evaluation and intervention if needed.

Short name

Fetal Thoracic Area

Frequently asked questions

Why might I need this test?
Your healthcare provider may recommend it if you have a history of pregnancy complications, certain medical conditions, or if your baby’s ultrasound shows unusual growth patterns.
How often will I have this test?
The frequency depends on your pregnancy status and healthcare provider’s recommendations. It’s often done during mid-pregnancy (around 18–22 weeks) but may vary.
What happens if the test results are abnormal?
If results are outside expected ranges, your provider will discuss next steps, which may include additional ultrasounds, genetic testing, or referral to a specialist for further evaluation.
  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