Double Marker Test Explained: Early Screening for Chromosomal Abnormalities
When a developing foetus has an extra or missing chromosome, it can cause medical problems. The most common chromosomal abnormalities include Down syndrome (or trisomy 21) which occurs when there is an extra copy of chromosome 21. This causes mental retardation, typical facial features, and, sometimes, birth defects. In Trisomy 13 and trisomy 18, there is an extra copy of chromosome 13 or chromosome 18. In such a case, pregnancy often ends in miscarriage. To detect chromosomal abnormalities, a screening test is done in the 11th and 13th weeks of pregnancy. It is called a double marker test . This test evaluates the levels of: 1. Free Beta hCG (Human Chorionic Gonadotropin): This hormone is produced by the placenta during pregnancy. Elevated levels may indicate chromosomal risks. 2. PAPP-A (Pregnancy-Associated Plasma Protein-A): This protein is produced by the placenta to maintain its health. Low levels may indicate placental issues or chromosomal disorders. The test offers sever...