How Reliable is NIPT in Twin Pregnancies?

How NIPT Works in Twin Pregnancies

During pregnancy, cell-free fetal DNA (cfDNA) from the placenta circulates in the mother’s blood. In twin pregnancies, DNA from both babies mixes in the mother’s bloodstream.

NIPT analyzes this combined DNA to screen for common chromosomal abnormalities such as:

• Down syndrome (Trisomy 21)
• Edwards syndrome (Trisomy 18)
• Patau syndrome (Trisomy 13)
• Sex chromosome abnormalities (with some limitations)

👉 Also Read: What is NIPT? Benefits, Accuracy, and When to Take the Test

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Accuracy of NIPT in Twins

• Down syndrome (Trisomy 21): Detection rate remains very high (over 95–99%).
• Other trisomies (18 & 13): Still accurate, but slightly lower than in singleton pregnancies.
• Sex chromosome conditions: More difficult to interpret, especially if twins are fraternal (dizygotic).

Key Differences from Singleton Pregnancies:

• The accuracy is slightly reduced because cfDNA comes from two placentas (or one in identical twins).
• NIPT cannot always tell which twin has the abnormality if a high-risk result is found.

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Benefits of NIPT in Twin Pregnancies

• Non-invasive & safe: Just a maternal blood draw, no risk to either baby.
• Early detection: Can be performed as early as 10 weeks.
• Accurate for Down syndrome: High reliability even in twin pregnancies.
• Peace of mind: Provides early reassurance for parents expecting multiples.

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Limitations of NIPT in Twin Pregnancies

While helpful, NIPT in twin pregnancies has some challenges:

• Cannot identify which twin may be affected.
• Accuracy is slightly lower compared to singleton pregnancies.
• Sex chromosome analysis may be inconclusive in fraternal twins.
• Vanishing twin syndrome (when one twin is lost early in pregnancy) can affect results.

👉 Next Read: Limitations of NIPT and When to Consider Diagnostic Testing

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When Should Parents of Twins Consider NIPT?

NIPT is especially valuable if:

• You are over 35 years old.
• There is a family history of genetic disorders.
• Ultrasound findings suggest possible abnormalities.
• You want early reassurance in a high-risk pregnancy.

However, results should always be confirmed with diagnostic testing (CVS or amniocentesis) if high risk.

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Final Thoughts

NIPT is a safe and reliable option for parents expecting twins, particularly for detecting Down syndrome. While not perfect, it provides valuable information early in pregnancy — helping parents prepare and doctors plan follow-up care.

If you’re carrying twins, discuss with your doctor or a genetic counselor whether NIPT is right for you, and how to interpret results alongside other screening tests.