What is Prenatal Testing?
What is prenatal testing and what are all the tests for?
Your doctor may have mentioned some prenatal testing to you. Maybe you’re confused about whether you need all the tests. Or maybe you’re wondering what all the tests are even looking for.
We know pregnancy can be completely overwhelming – especially if this is your first baby and all of this is brand-new. It’s normal to worry or be nervous about your baby’s health. And it’s normal to feel overcome by all the decisions you have to make. We want to help give you the information you need so you can make decisions knowing the risks and benefits.
So let’s break this down and talk about what prenatal testing is, what tests are involved, what information they give and what the risks may be.
Prenatal tests are medical tests you have during your pregnancy. These tests can give your doctor some clues about your baby’s health.
- Ultrasound – This is a noninvasive test that can show your baby’s development. The ultrasound uses sound waves and a computer screen to show pictures of your baby in your womb. An early ultrasound can confirm pregnancy and help determine how many weeks pregnant you are. In later ultrasounds, the sonographer or physician will check to make sure your baby is developing normally through various measurements and organ evaluation, as well as evaluation of your uterus and placenta location.
- Cell–free DNA testing – This is also a noninvasive test and done through a simple blood draw. This test screens your baby’s DNA to check for markers for any genetic conditions. Usually, your doctor won’t order this screening unless another test suggests your baby could have a genetic abnormality.
- Chorionic villus sampling – (also called CVS) This is a diagnostic test that checks tissue from the placenta to see if your baby has a genetic condition. This test is usually done at 10 – 12 weeks of pregnancy and only if your doctor has a reason to believe your baby has a chromosomal abnormality. Because a needle is introduced into the uterus, there’s a chance of miscarriage with this test. The American College of Obstetricians and Gynecologists (ACOG) reports that 1 in every 100 women who has this test will have a miscarriage.
- Quad screening – This is a blood test that measures four substances in your blood (alpha-fetoprotein (AFP), estriol, human chorionic gonadostropin (hCG) and inhibin A). This test is done sometime between weeks 15 and 22. Your doctor uses these results to predict whether your baby is more or less at risk for some birth defects.
- Amniocentesis – (also called amnio) In this test, your doctor removes amniotic fluid and tests it to see if your baby has a genetic condition (like Down Syndrome). It’s usually done at 15 – 20 weeks of pregnancy. Like CVS, the amniocentesis is an invasive test and comes with risk of miscarriage. According to the American Pregnancy Association, the risk of miscarriage with an amniocentesis ranges from 1 in 200 to 1 in 400, depending on the timing and how often the facility performs amniocenteses.
Now you might be wondering, since you have to make a decision about all these tests, should you just say yes to everything? Here are some things to consider:
What will you do with the results?
If the results are normal, that might put your mind at ease. But if the results of a screening indicate your baby might have a birth defect, you could be faced with some hard decisions. Do you want to have a more invasive diagnostic test that could put you at risk for a miscarriage? Your doctor may offer the option of an abortion, so you may be faced with that difficult decision.
Of course, knowing your baby could be at risk for some medical problems can also help you prepare in advance for your baby’s care. Some prenatal tests can detect problems that can be treated during pregnancy. Others can let you know of care or treatment your baby will need immediately after birth.
How accurate are the results?
The rate of false-positives or false-negatives varies from test to test. Before you make a decision, ask your doctor how accurate the results are.
If you’re feeling overwhelmed by all the prenatal testing decisions you have to make, we’d encourage you to visit with your doctor and express your concerns. We know that it can be uncomfortable at times asking a lot of questions, but you deserve to get the information you need in order to make an informed decision. If need be, bring your husband, your partner, a good friend or family member with you to your appointment to help you process. Having someone with you may lighten your load and help you to not feel so overwhelmed. And remember, you don’t have to make the decision that day. You have time to determine what’s right for you.
