Prenatal Genetic Screening

Types of Prenatal Genetic Screening

First Trimester Combined Screening (11–13 weeks)

The NT scan combined with blood tests (PAPP-A and free beta-hCG) provides a risk assessment for Down's syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), and Patau syndrome (Trisomy 13). This is a screening test — it gives a risk probability, not a definitive diagnosis.

NIPT — Non-Invasive Prenatal Testing (10+ weeks)

NIPT analyses cell-free fetal DNA in the mother's blood to screen for chromosomal abnormalities with high accuracy (>99% sensitivity for Trisomy 21). It is non-invasive — a simple blood draw — and has no risk of pregnancy loss. NIPT is increasingly recommended for all pregnancies, not just higher-risk ones.

Anomaly Scan (18–20 weeks)

A detailed Level II ultrasound evaluating fetal anatomy for structural abnormalities — heart defects, neural tube defects, renal anomalies, and more.

Amniocentesis (15–20 weeks)

A small sample of amniotic fluid is taken to obtain fetal cells for chromosomal analysis. Provides a definitive diagnosis. Carries a small risk of pregnancy loss (approximately 0.5–1%) — Dr. Juneja counsels thoroughly before this procedure.

CVS — Chorionic Villus Sampling (11–14 weeks)

Placental tissue is sampled for early definitive chromosomal diagnosis. Allows diagnosis in the first trimester. Similar small risk of pregnancy loss as amniocentesis.

Who Should Consider Enhanced Genetic Screening?

• Women aged 35 or over at delivery
• Couples with a family history of chromosomal or genetic conditions
• Previous pregnancy with a chromosomal abnormality
• Abnormal first trimester combined screening result
• Fetal structural abnormality detected on ultrasound
• Parents who are known carriers of a genetic condition