Skip to content

Fetal Diameter Measurement (Abdominal Ultrasound)

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

This test uses ultrasound to measure the size of your baby’s abdomen to help track growth during pregnancy.

Quick summary

["Ultrasound checks fetal development and health by measuring abdominal size."]

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

Key facts at a glance

LOINC
53669-8
Short code
Fet R eye Diam US.meas
Synonyms
Fet R eye Diam 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

Why This Test Is Done

Your healthcare provider may order this test to monitor your baby’s growth, check for potential developmental concerns, or assess the position of the placenta. It’s often performed during routine prenatal visits, especially in the second trimester.

What to Expect During the Test

You’ll lie on your back on an exam table with a gel applied to your abdomen. A transducer (a handheld device) will glide over your skin to capture images of your baby’s abdominal area. The test usually takes about 20–30 minutes and is painless.

How the Results Are Used

The results help your provider compare your baby’s size to expected growth patterns. If measurements fall outside typical ranges, further evaluation may be needed to rule out conditions like intrauterine growth restriction or other complications.

Common Reasons for Abnormal Results

Low fetal abdominal diameter may signal concerns like poor growth, chromosomal abnormalities, or placental issues. High measurements could indicate polyhydramnios (excess amniotic fluid). Always discuss findings with your healthcare team.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Abdominal Fetal Size

Frequently asked questions

When will I get my results?
Results are typically reviewed by your healthcare provider during your next prenatal visit. They’ll discuss any findings with you and recommend next steps if needed.
Is this test painful?
No, the ultrasound itself is painless. You may feel slight pressure or warmth from the gel, but no discomfort.
Can I eat or drink before this test?
You can eat and drink normally before the test, as it doesn’t require fasting. Wear comfortable clothing and bring your prenatal records if you have them.
  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