Are you at risk of carrying a baby with Down syndrome in your pregnancy? Should you go for screening or diagnostic tests? Which Down syndrome tests are more accurate to detect Down syndrome in a baby? All these questions are answered here.
A Bit about Down Syndrome
Down syndrome occurs due to chromosomal abnormalities in a baby. In a normal baby during the time of conception, the number 21 chromosome from the father mingles with number 21 chromosome from the mother to form a set of paired chromosomes. A normal baby has 46 such chromosomes arranged in 23 pairs.
In case of a Down syndrome baby, during the pairing, a third chromosome number 21 joins in. So instead of a pair, the Down syndrome baby has three of that particular chromosome. This duplication happens for all the cells of the baby.
So Why Is It A Problem?
A Down syndrome child will have learning difficulties; they may be different in their outward appearance, and can develop medical conditions like heart defects, birth defects etc. Also their average life span will range between 50-60 years.
So in order to know if you are carrying a baby with Down syndrome, you can opt for screening and diagnostic tests to test for Down syndrome.
More about Screening Tests
Currently there are three screening tests available for Down syndrome. The detection rate of these tests is not very accurate guaranteeing up to 60% to80% of detection.
First Trimester Screening
There are two types of tests done during the first trimester. They are the blood test and the NT scan (nuchal-translucency).The Down syndrome blood test during pregnancy detects for hCG (human chorionic gonadotrophin), PAPP-A (pregnancy associated plasma protein) in mother’s blood. If the level of these substances is abnormal then test turns out to be screen positive.
NT scan is an ultrasound scan to measure the fluid of the skin behind the baby’s neck. The accuracy of these tests depends on the skills of the doctor and also on the scanning machine.