Which type of prenatal screening tests for chromosomal abnormalities?

• A. Amniocentesis
• B. Chorionic villus sampling (CVS)
• C. Non-invasive prenatal testing (NIPT)
• D. Ultrasound scanning

Answer: (C)

Non-invasive prenatal testing (NIPT) is designed specifically to screen for chromosomal abnormalities in the fetus. It analyzes cell-free fetal DNA circulating in the maternal blood to assess the risk of conditions such as Down syndrome (trisomy 21) and other trisomies (like trisomy 18 and 13). NIPT is highly sensitive and has a low false-positive rate, making it a preferred choice for many expectant mothers who wish to understand the risk of chromosomal anomalies without invasive procedures.

In contrast, amniocentesis and chorionic villus sampling (CVS) are invasive procedures that provide definitive diagnostic information rather than screening. While both tests can identify chromosomal abnormalities, they carry a risk of complications, such as miscarriage. Ultrasound scanning plays a supportive role in prenatal care, helping to assess fetal anatomy and development but it is not specifically used for detecting chromosomal abnormalities on its own.

Therefore, NIPT stands out as the non-invasive option specifically aimed at screening for chromosomal abnormalities, aligning with the intent of the question.