Incredible Science: Prenatal Testing for Baby’s Genetic Health
Your baby’s health is bound to be your main concern. Of course, you know that prenatal care will help you live your pregnancy stage by stage and monitor your baby’s healthy growth. You will do a number of tests at different stages which will help you follow your baby’s development. Your prenatal visits can be very exciting and a great time for you to ask all your questions.
In some cases, you will need to some special in-depth tests. These tests may be suggested to you if doctors suspect some illness that could be linked to genetics. Your baby’s genetic health can only be fully assessed by means of DNA testing but not all mothers need to undergo genetic screening of their baby. An actual DNA test will in fact only be carried out if any other tests (such as ultrasounds or maternal serum tests) indicate something could be wrong, an abnormality in the values of the results. If standard prenatal tests are all in line and within the norm, then there will be no need to carry out further genetic tests. By the way, half of all women who get pregnant over the age of 35 have some type of genetic test.
The two main tests you may have to undergo
Depending on the week of pregnancy you are in, one of these two diagnostic tests will be recommended: amniocentesis and chorionic villus sampling. They are the medical terms but it is worth knowing them as these are the terms that you might be hearing. These two baby DNA sample collection procedures are also used for establishing the father during pregnancy.
The first test, amniocentesis, test involves withdrawing a volume of amniotic fluid from the amniotic sac. Of course, the fluid needs to be withdrawn and to do this you will need an OBGYN. Don’t panic: it is a quick, painless procedure and you will not need to wait long for it to be over. Withdrawing the actual fluid only takes 5- 10 minutes at most. Before withdrawing the fluid, they will need to take an ultrasound to check what position your baby is in.
Withdrawing fluid is done with a syringe. The OBGYN will insert it into your abdomen and into your womb. To make sure you do not even feel the prick, some local anesthetic will be rubbed onto your belly. Once extracted, you could, perhaps feel a bit of soreness because of the extraction but this could happen even with a flu jab and the feeling is no different in this case.
This sample of fluid is then sent to a laboratory for analysis.
Chorionic villus sampling is carried out earlier in pregnancy then amniocentesis and this is an important point as the stage of pregnancy affects which type of test is carried out. Amniocentesis is carried out between the 15th and the 20th week of pregnancy whilst chorionic villus sampling (or CVS for short) is carried out before 15 weeks. The procedure you will undergo is not too different from amniocentesis (by the way many people just refer to it as an “amnio”). CVS too will need to be done by an OBGYN who will insert a needle into your womb to collect a tiny, tiny sample of tissue. By the way, in some case, he or she can also take this sample of tissue by passing a catheter through the opening of your womb via the vagina. Both the sample of tissue collected in CVS and the sample of amniotic fluid collected via an amnio can then be lab analyzed to see whether your baby has any genetic defects.
What type of genetic defects are we talking about?
There are many genetic defects which can be detected with such tests:
- Tay-Sachs disease
- sickle cell anemia
- cystic fibrosis
- Down syndrome
- Neural tube defects (for example, spina bifida)
- Edward syndrome
- Turner’s syndrome
- Fragile X
And the above list is far from complete. There are many, many more conditions which can be detected thanks to these two simple baby DNA sample collection procedures. One important thing is that both amnio and CVS have a small risk of miscarriage.
About the author: Helen McArthur is a part time free lance writer specializing in pregnancy and prenatal care. Helen worked as a nurse in the prenatal care unit for several years before putting her career on hold to look after her kids. A number of articles by the author can be found in the article repository for homeDNAdirect.
Have you undergone prenatal testing before, and if not, would you choose to? Share your thoughts in the comments!
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