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Fetal Interventricular Septum Thickness Measurement

Published: August 9, 2026Updated: August 17, 2026

A prenatal ultrasound test that measures the thickness of the wall between the heart's two lower chambers in an unborn baby. Using a special motion-tracking imaging technique, this measurement helps doctors assess whether the fetal heart is developing normally and can point to possible congenital heart defects early in pregnancy.

Quick summary

{"Uses sound waves to measure the wall thickness between the heart's ventricles","Helps detect congenital heart defects before birth","Performed during routine pregnancy ultrasound screenings","No radiation or pain involved for mother or baby","Results help doctors plan appropriate care during delivery"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
12152-5
Short code
Fet IVS Thickness.sys US.M-mode+Meas
Synonyms
Fet IVS Thickness.sys US.M-mode+Meas
Category
cardiac
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-m-mode-measured
CPT
82553
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 is this test?

This test uses ultrasound technology (specifically M-mode) to measure the thickness of the interventricular septum—the wall that separates the two lower chambers (ventricles) of the fetal heart. During pregnancy, this measurement helps doctors assess whether the baby's heart is developing normally.

How is the test performed?

A trained sonographer or doctor will place a gel on your abdomen and use a handheld device called a transducer. This device sends sound waves that bounce off the baby's heart, creating images on a screen. The M-mode specifically tracks the motion of heart structures over time, allowing for precise measurement of the septal thickness during heartbeats.

Why is this test important?

Measuring the interventricular septum thickness helps identify potential heart abnormalities early in pregnancy. If the septum is abnormally thick or thin, it may indicate congenital heart defects that may require special care or surgery after birth. Early detection allows your healthcare team to prepare for any needed interventions.

Is it safe?

Ultrasound is considered safe for both mother and baby. It uses sound waves instead of radiation, and there are no known risks associated with the standard prenatal ultrasound examinations. The test is painless and typically takes 15-30 minutes.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal interventricular septal thickness may indicate conditions such as hypertrophic cardiomyopathy, ventricular septal defects, or other congenital heart abnormalities. This measurement is part of a comprehensive assessment of fetal cardiac anatomy and helps guide pregnancy management and delivery planning. If abnormalities are detected, further testing such as fetal echocardiography may be recommended.

Frequently asked questions

When is this test typically performed?
This test is usually performed during the second trimester (around 18-22 weeks) as part of the detailed anatomy ultrasound. It may also be done earlier or later depending on your pregnancy risk factors or if your doctor suspects a heart abnormality.
Do I need to prepare for the test?
No special preparation is needed. You may be asked to drink water before the exam to help with image clarity, as a full bladder can sometimes improve ultrasound visualization.
What happens if abnormal results are found?
If the septal measurement is abnormal, your doctor will likely recommend additional testing, such as a fetal echocardiogram (a detailed ultrasound of the baby's heart). This helps determine the exact nature of any heart condition and allows your healthcare team to plan for appropriate care after delivery.
Does an abnormal result always mean a heart problem?
Not necessarily. Measurements must be interpreted in context with other findings. Sometimes variations can be normal, or they may require follow-up to confirm. Your doctor will explain what the results mean for your specific situation.
  1. 1
    American College of Obstetricians and Gynecologists - Fetal EchocardiographySource
  2. 2
    Mayo Clinic - Fetal EchocardiogramSource
  3. 3
    CDC - Congenital Heart DefectsSource

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 17, 2026. · Read our editorial policy