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Fetal Abdomen Percentile, Circumference, Estimated Gestational Age

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

This test uses ultrasound measurements of the fetal abdomen and head to estimate fetal size, calculate an abdominal circumference percentile, and estimate gestational age.

Quick summary

["Fetal biometry helps your care team track your baby's growth and estimate how far along the pregnancy is."]

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

Key facts at a glance

LOINC
96125-0
Short code
Fet Abd Prctl Circum Per est GA
Synonyms
Fet Abd Prctl Circum Per est GA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
per-estimated-gestational-age
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

During a prenatal ultrasound, the sonographer measures the baby's head and abdominal circumference. These measurements are compared with standardized growth charts to calculate an abdominal circumference percentile and to estimate gestational age.

Why It Is Done

This measurement is commonly part of routine pregnancy ultrasound exams. It helps assess whether the baby's growth is appropriate for the stage of pregnancy and can flag concerns such as growth restriction or overgrowth.

How to Prepare

No special preparation is usually needed. You may be asked to drink water before the exam or follow your clinic's instructions. Ultrasound is noninvasive and generally painless.

What the Results Mean

Your clinician interprets the percentile and estimated gestational age together with other ultrasound measurements, your pregnancy history, and your due date. A single measurement is rarely conclusive, and follow-up imaging may be recommended.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Fetal abdominal circumference percentile and estimated gestational age are key components of obstetric ultrasound assessment. They help evaluate fetal growth, screen for conditions such as fetal growth restriction or macrosomia, and guide decisions about monitoring and timing of care. Results should always be interpreted by a qualified clinician in the context of the full clinical picture.

Short name

Fetal Abdominal Circumference Percentile

Frequently asked questions

Does this test hurt?
No. It is a standard ultrasound measurement and is noninvasive and generally painless.
Can one ultrasound result show a growth problem?
Not usually. A single measurement must be interpreted with other findings and clinical context; your clinician may recommend repeat imaging.
Do I need to fast before this test?
Typically no. Follow any specific instructions from your clinic, such as drinking water before the appointment.
  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