Antenatal tests are usually done on pregnant women, and they help find out whether the baby has any chromosomal abnormalities such as Down syndrome, or any other conditions that can affect the unborn baby, such as spina bifida.
These tests are, however, your choice, but it is always wise to have them done. The reason behind this is that when you know that your child has a health abnormality, you can get the right medical advice as early as possible.
Now, human cells usually have 46 chromosomes. Abnormalities happen when there are missing chromosomes or if your baby has extra. They could also be altered in one way or the other. Read on to learn more about what affects the baby’s health and pregnancy testing.
Abnormalities and More
Additionally, there are many different types of these chromosomal abnormalities and most of them cause intellectual or physical disabilities in kids. These abnormalities include Edwards’ syndrome, Down syndrome, and Patau syndrome.
Of course, there are many other conditions that can cause these abnormalities during pregnancy, but when you have these tests done, you can rule out chromosomal influence.
How Are They Done?
Antenatal screening tests usually determine the risk for your baby, and the result of the tests will usually say that your baby has a high or low risk.
If the results you get show that your baby has a high risk, then the hospital can offer you additional diagnostic tests.
Diagnostic tests usually give you either a yes or a no, as to whether your baby has a condition or not. They also pick up on a wide range of many other chromosomal abnormalities.
Types of Screening Tests
There are many different types of these tests, and they include the following.
Non-Invasive Prenatal Testing – NIPT
This test seeks to look into the risk of your baby having specific chromosomal abnormalities. The test involves a very simple blood test, where a small amount of blood is collected.
They also collect DNA from the baby’s placenta and test it.
You can have this test run from 10 weeks of pregnancy onwards. NIPT is more accurate than any other screening test, but it is also extremely expensive, and you might hear it being called a cell-free DNA or a cfDNA test.
The Combined First Trimester Screening
This is the CFTS test, and it looks at the risk of the baby having specific chromosomal abnormalities. It usually combines a blood test from the mother and another test from your 12-week ultrasound scan.
You can have this test run between 8-12 weeks of pregnancy, and it measures the levels of two different hormones in your blood.
The 12-week ultrasound is a very common test in pregnancy, and if you decided to combine it with the first-trimester screening, the professional will also do an ultrasound to measure the amount of fluid at the back of your baby’s neck. This is usually called the Nuchal Translucency scan.
Second Trimester Screening
This is also known as the maternal serum, and it looks at the risk of having certain abnormal chromosomes in the baby. It is a simple blood test, and they usually test your blood for hormones from your placenta to the baby.
Your hormone levels, age, weight, and your baby’s gestational age are used to estimate the risk of your baby having some chromosome-related abnormalities.
The test is best done between 14 and 20 weeks into a pregnancy.
This test also looks at the risk of your baby having a neural tube defect such as Spina Bifida. This confirms whether your baby has this condition, and you may need to have an ultrasound, as well.
The Down Syndrome Risk
All screen tests for chromosomal abnormalities will always take the age of the pregnant mother into account. This is due to the fact that the risk increases as per your age for a baby to be born with Down syndrome. Here are some relevant statistics.
- 20-29 years, the risk is less than 1 in 1000
- 30 years, the risk is 1 in 890
- 35 years, the risk is 1 in 355
- 37 years, the risk is 1 in 220
- 40 years, the risk is 1 in 90
- 45 years, the risk is 1 in 28
These are well-researched tests that women all over the world have had done.
They do not pose any risk to the unborn baby, and they are ideal for any woman who has a genetic history of specific chromosomal abnormalities. To learn more about pregnancy tests, click here.