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Estimated Gestational Age at Birth (via Umbilical Cord Blood)

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

This test helps determine how far along your pregnancy was at the time of delivery by measuring certain substances in your baby’s blood from the umbilical cord.

Quick summary

["This test supports medical decisions about your baby’s health and development at birth."]

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

Key facts at a glance

LOINC
72147-2
Short code
GESTATIONALAGEATBIRTH
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rhea
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?

Doctors may use this test to confirm or refine the gestational age estimate if there’s uncertainty about how far along the pregnancy was. It can also help assess fetal maturity or rule out potential complications like preterm birth.

What Does the Test Measure?

The test analyzes specific biomarkers in the umbilical cord blood, which reflect the baby’s physiological development during pregnancy. These markers can indicate whether the baby was born at term, preterm, or post-term.

How Is the Sample Collected?

A small sample of blood is taken directly from the umbilical cord immediately after birth. This is a quick and safe procedure performed by healthcare providers during delivery.

What Happens Next?

The sample is sent to a lab for analysis. Results are typically available within a few days and can be used alongside other prenatal records to guide care decisions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test plays a critical role in identifying gestational age discrepancies that may influence neonatal care, such as the need for respiratory support, feeding adjustments, or monitoring for developmental risks.

Short name

Gestational Age Assessment

Frequently asked questions

Why might my doctor request this test?
Your doctor may order this test if there’s any doubt about your baby’s gestational age based on other prenatal assessments, such as ultrasound results or last menstrual period estimates.
What are the possible results and what do they mean?
Results may indicate the baby was born at term (around 37–42 weeks), preterm (before 37 weeks), or post-term (after 42 weeks). These findings help guide decisions about neonatal care, such as whether extra monitoring or interventions are needed.
Is this test painful or risky for my baby?
No, this test is not painful for your baby. The blood sample is taken from the umbilical cord immediately after birth, and it is a standard part of the delivery process.
  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