Down syndrome (trisomy 21) testing in India includes highly sensitive screening tests — NIPT (99% accuracy) and combined first-trimester screening (~85–90%) — as well as definitive diagnostic tests (CVS and amniocentesis). This guide explains each option, costs, and what to do when results come back.
What Is Down Syndrome?
- Caused by an extra copy of chromosome 21 (trisomy 21) in every cell of the body
- Occurs in approximately 1 in 800 live births globally
- Risk increases with maternal age — but 80% of cases occur in women under 35
- Associated with intellectual disability, characteristic physical features, and increased risk of heart defects, hearing loss, and thyroid issues
- Most people with Down syndrome live into their 60s and beyond with appropriate support
- Not caused by anything the mother or father did — it is a random chromosomal event
Screening Tests for Down Syndrome
Screening tests estimate the probability of Down syndrome. They do not confirm the diagnosis — they identify pregnancies that need further investigation.
NIPT (Non-Invasive Prenatal Testing)
NIPT analyses cell-free fetal DNA in the mother's blood and is the most accurate prenatal screening test available. It can be done from 10 weeks of pregnancy with no risk to the baby.
- Detection rate for Down syndrome: ~99%
- False-positive rate: <0.1%
- Cost in India: ₹8,000–₹22,000 depending on panel
- Result time: 7–14 days
Combined First-Trimester Screening (11–14 weeks)
Combines a nuchal translucency (NT) ultrasound measurement with maternal blood markers (PAPP-A and free beta-hCG). Widely available across India.
- Detection rate for Down syndrome: ~85–90%
- False-positive rate: ~5%
- Cost in India: ₹3,000–₹6,000
Quadruple (Quad) Screen (15–20 weeks)
Second-trimester blood test measuring AFP, hCG, estriol, and inhibin-A. Used when first-trimester screening was missed.
- Detection rate for Down syndrome: ~75–80%
- False-positive rate: ~5%
- Cost in India: ₹2,500–₹5,000
Diagnostic Tests: Getting a Definitive Answer
Diagnostic tests analyse the baby's actual chromosomes and give a definitive yes/no answer. They are recommended when screening tests return a high-risk result.
A small sample of placental tissue is taken. Results in 2–5 days (FISH) or 2–3 weeks (full karyotype). Cost: ₹12,000–₹20,000. Miscarriage risk: ~0.5–1%.
A sample of amniotic fluid is taken. Results in 2–3 weeks. Gold standard for chromosomal diagnosis. Cost: ₹8,000–₹15,000. Miscarriage risk: ~0.1–0.3%.
Important: Diagnostic tests confirm whether Down syndrome is present — they cannot predict the severity of intellectual disability or developmental outcomes, which vary widely among individuals with Down syndrome.
Down Syndrome Risk by Maternal Age
| Maternal Age | Risk of Down Syndrome | Risk (1 in N) |
|---|---|---|
| 25 years | 0.08% | 1 in 1,250 |
| 30 years | 0.11% | 1 in 952 |
| 35 years | 0.26% | 1 in 378 |
| 37 years | 0.47% | 1 in 212 |
| 38 years | 0.57% | 1 in 175 |
| 40 years | 1.0% | 1 in 100 |
| 42 years | 1.67% | 1 in 60 |
| 45 years | 3.3% | 1 in 30 |
Age-related risk is a baseline population risk. Your individual risk is modified by prior affected pregnancies, family history, and — most importantly — your screening test results. A 40-year-old woman with a low-risk NIPT result has a very low probability of an affected pregnancy.
After a Diagnosis: What Are Your Options?
A confirmed Down syndrome diagnosis is a deeply personal moment. It is important to make decisions with full information, without time pressure, and with appropriate emotional support.
Many families choose to continue and prepare — connecting with Down syndrome support groups (like DSFI), paediatric cardiologists, and early intervention programmes in India.
Legal in India under the MTP Act for chromosomal conditions, with gestational limits. Requires medical consultation. A personal decision made by the family.
"There is no right or wrong decision — only the decision that is right for your family, made with complete information. A genetic counselor's role is to provide that information and support, not to guide you toward any particular choice."
Speak With a Prenatal Genetic Counselor
Lakshita Thakore is a BGCI Certified Genetic Counselor with expertise in prenatal diagnosis. She can guide you through Down syndrome testing options and results.
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