When Should You Do the Triple Marker Test During Pregnancy? — Complete Guide
Introduction
Pregnancy is a beautiful phase filled with joy, excitement, and new experiences. It is also a time when mothers undergo several important tests to ensure the baby’s health and development. Among the second-trimester screening tests, the triple marker test in pregnancy is one of the most commonly recommended.
Many expecting mothers have questions such as:
- When should this test be done?
- Why is it important?
- Does every pregnant woman need it?
- What conditions does it check for?
This detailed guide explains everything about the triple marker test, its timing, benefits, interpretation, and why doctors suggest it even if your scan looks normal.
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What Is the Triple Marker Test?
The triple marker test in pregnancy is a blood screening test done during the second trimester. It helps evaluate the risk of the baby having chromosomal abnormalities or neural tube defects. The test measures three important substances in the mother’s blood:
- AFP (Alpha-Fetoprotein)
A protein produced by the baby’s liver. Abnormal levels may indicate neural tube defects such as spina bifida or anencephaly.
- hCG (Human Chorionic Gonadotropin)
A hormone produced by the placenta. High or low levels may suggest chromosomal disorders such as Down syndrome.
- Estriol (Unconjugated Estriol)
A hormone produced by the placenta and baby’s liver. Low levels may indicate genetic abnormalities or placental concerns.
These three markers together help doctors understand whether the baby has a higher chance of certain conditions.
Ideal Time to Take the Triple Marker Test
The triple marker test should be done:
Between 15 to 20 weeks of pregnancy
The most accurate period is 16 to 18 weeks.
Why this timing?
During this period, the levels of AFP, hCG, and Estriol are well-established in the bloodstream and provide reliable screening information.
If a mother misses the NT scan or double marker test (usually done between 11–14 weeks), the triple marker test becomes an important alternative.
Who Should Consider Taking the Triple Marker Test?
While the triple marker test in pregnancy is optional, doctors may recommend it strongly if:
✓ You missed the first-trimester double marker test
Many mothers visit late or skip early screening.
✓ You are above 30–35 years of age
Increasing maternal age increases the risk of chromosomal abnormalities.
✓ There is a family history of genetic disorders
For example: Down syndrome, Trisomy conditions, neural tube defects.
✓ The NT scan or ultrasound showed a “soft marker”
Such as:
- Thickened nuchal fold
- Echogenic bowel
- Mild ventriculomegaly
- Short nasal bone
✓ You have thyroid imbalance, diabetes, or autoimmune conditions
✓ You simply want reassurance about the baby’s development
Many mothers take this test for peace of mind.
Conditions the Triple Marker Test Screens For
The triple marker test does not diagnose conditions but estimates the chances of:
- Down Syndrome (Trisomy 21)
A genetic condition that affects physical and brain development.
- Edwards Syndrome (Trisomy 18)
Associated with severe structural abnormalities.
- Neural Tube Defects
Such as:
- Spina bifida
- Anencephaly
- Other chromosomal and developmental abnormalities
While the test cannot confirm any condition, it indicates whether the mother needs further testing.
Accuracy of the Triple Marker Test
The triple marker test is a screening test, not a diagnostic test.
Accuracy levels:
- Down syndrome detection: 70–80%
- Neural tube defect detection: 80–85%
It provides a statistical risk, not a guaranteed result.
If the test shows high risk, doctors may recommend:
- NIPT (Non-Invasive Prenatal Testing)
- Detailed fetal anomaly scan
- Amniocentesis (for final confirmation)
How the Test Is Done?
The triple marker test in pregnancy is simple and safe.
- Only a small blood sample is taken
- No fasting is required
- Results come in 3–5 days
- No risk to baby or mother
Understanding the Report
The report displays:
- AFP level
- hCG level
- Estriol level
- MoM (multiple of median) values
- Final risk ratio for each condition
Low Risk
Meaning the chances of abnormalities are low.
High Risk
You will be advised for follow-up tests.
High risk does not mean your baby definitely has a problem—only that the chance is higher.
📲 Book your scan with confidence
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FMF-certified Fetal Medicine Specialists • Advanced Ultrasound
Founder of Nisarga Diagnostics, is a renowned fetal ultrasound specialist with over 20 years of expertise. An alumnus of Government Medical Colleges in Mysore and Bangalore, he also holds a D.N.B. from the National Board of Examinations, Delhi, and certification from the Fetal Medicine Foundation, London. A former Professor and HOD, he has trained countless PG students and junior radiologists, shaping the future of fetal imaging in India.