Genetic testing is also available for those who are already pregnant. Such medical tests are usually done in the early stages of pregnancy, to either allow preparation for a child with the condition, or to allow for termination of pregnancy. These are known as antenatal genetic tests, or prenatal tests.
Genetic testing performed in pregnancy can help identify whether a developing fetus has a genetic or chromosomal issue. There are a few main types of antenatal genetic tests:
- Non-invasive prenatal testing (NIPT)
NIPT involves a blood test on the mother, performed after 9 weeks of pregnancy.
This prenatal test can then help indicate whether your baby has a high chance of having a chromosomal condition. This test will also tell you the gender of the baby.
Undergoing NIPT can then help you decide whether you might like to have a more invasive test. Chorionic villus sampling (CVS) and amniocentesis are more invasive diagnostic tests that can be performed in pregnancy.
Chorionic villus sampling (CVS)
Chorionic villus sampling (CVS) is a genetic test that is usually performed between 10 – 12 weeks of pregnancy.
This prenatal test involves inserting a needle, either into the mother’s abdomen or vagina, to remove a small part of the developing placenta.
That sample, which contains genetic material, is analysed to detect genetic issues in the fetus.
Amniocentesis
Alternatively, amniocentesis can be performed later in the pregnancy, around week 15 – 20.
Amniocentesis involves inserting a needle into a pregnant woman’s abdomen to take some amniotic fluid.
Amniotic fluid is the fluid that surrounds the developing baby, and it contains skin cells that have shed from the developing baby. That fluid can then be checked to see if there are genetic issues in the fetus.
