What Is Prenatal Testing?
When you're pregnant, prenatal tests give you information about your and your baby's health. These tests help spot any problems that could affect them, such as birth defects or genetic diseases. The results can help you make the best health care decisions before and after your child is born.
Prenatal tests are helpful, but it's important to understand what they find. A positive test result doesn't always mean your baby will be born with a disorder. You'll want to talk with your doctor, midwife, or other health care provider about what the tests mean and what you should do once you have the results.
Doctors recommend some prenatal tests for all pregnant people and other screening tests only if the baby is at risk for certain genetic problems.
Is prenatal testing covered by insurance?
That depends on the test and your insurance coverage. Many health insurance plans will cover prenatal tests that your doctor considers medically necessary. But each plan has different rules about which tests it will cover.
Prenatal tests can range from a few hundred dollars to several thousand dollars per test. If your insurance covers the cost, you'll pay less. A basic prenatal blood panel that is recommended for all pregnancies costs around $260 and is usually covered by insurance. Noninvasive prenatal testing (NIPT), which checks your blood for chromosomal disorders and other genetic problems, costs more than $1,000 and is sometimes covered by insurance. Amniocentesis costs more than $4,000 without insurance.
Call your insurance company before you get tested to ask what your plan will cover and what you'll have to pay out of pocket.
Are there any side effects to prenatal testing?
Routine prenatal tests that involve a blood test or ultrasound don't have any side effects. Amniocentesis and chorionic villus sampling (CVS) involve placing a needle into your uterus. These tests do carry risks such as:
- Bleeding. A little bleeding is normal, but heavy bleeding can also sometimes happen.
- Infection. There is a slight risk of infection whenever a needle is placed into the skin.
- Miscarriage. The risk is very low — less than 1%. Miscarriage is less likely to happen when amniocentesis is done after week 15 of pregnancy.
- Leaking amniotic fluid. This fluid surrounds your baby. Usually, the amount of amniotic fluid loss isn't enough to affect the pregnancy, but it's possible.
- Injury to the baby. Rarely, the baby's arm or leg might move in front of the needle, but serious injuries from a needle are rare.
- Rh sensitization. If you have Rh-negative blood and your baby has Rh-positive blood, your body could develop antibodies against your baby's blood. Your doctor can give you medicine called Rh immune globulin to prevent this.
Routine Prenatal Testing
You can get prenatal tests in your first, second, and third trimesters. Some check your health, and others give information about your baby.
Throughout your pregnancy, you'll get routine exams to make sure you're healthy. Your health care provider will check samples of your blood and urine for certain conditions, including:
- HIV and other sexually transmitted diseases
- Anemia
- Diabetes
- Hepatitis B and hepatitis C
- Preeclampsia, a type of high blood pressure
- Rubella, an illness caused by a virus
- Tuberculosis (TB)
They'll also check your blood type and whether your blood cells have a protein called the Rh factor. You may also get:
- A Pap test
- Group B Strep screening. Your doctor will swab the skin in and around your vagina and your rectum to check for this type of bacteria. This usually happens in the last month before you give birth.
- Ultrasound. This technology uses sound waves to make pictures of your baby and your organs. If your pregnancy is normal, you'll have it twice, once near the beginning to see how far along you are, and again around 18-20 weeks to check your baby’s growth and make sure their organs are developing properly.
Genetic Prenatal Testing
Doctors can also use prenatal tests to look for signs that your baby is at risk for certain genetic disorders or birth defects. You don't have to have these tests, but your doctor may suggest some to make sure your baby is healthy.
They're especially important for women with a higher risk of having a baby with a birth defect or a genetic problem. You may have a higher risk if you:
- Are over 35
- Have had a premature baby or a baby with a birth defect
- Have a genetic disorder or one that runs in your family or the other parent’s family
- Have been exposed to a medication or chemical that might be harmful to the baby
- Have had miscarriages or stillborn babies in the past
Some prenatal genetic tests are screening tests. They tell you if your baby is at a higher risk for a certain disorder or disease, but they can’t tell you for certain that the baby will be born with it. Diagnostic tests give you a clearer answer. Usually, you'll get this kind of test after you have a positive result on a screening test.
Carrier screening. To start, your doctor may want to test you and the child's other parent to see if either of you carries the genes that cause certain genetic diseases, such as cystic fibrosis, Tay-Sachs disease, and sickle cell disease. If both of you have a gene for one of these diseases in your DNA, you could pass it on to your baby, even if you don't have the disease yourselves.
Your doctor can use one or more different screening tests to check your baby for a genetic problem, including:
Ultrasound. You'll have one of these early in your pregnancy to make sure everything is going well. But if you have a high-risk pregnancy, you'll need this exam more often. Around 11-14 weeks, doctors can use it to look at the back of your baby's neck. Folds or thick skin there could mean a higher risk of Down syndrome. Your doctor may take a sample of your blood at the same time.
Cell-free fetal DNA testing. Doctors use this test to find your baby's DNA in your blood and check it for Down syndrome, caused by an extra copy of chromosome 21. This test also checks for two other genetic conditions, trisomy 18 and trisomy 13. "These types of chromosomal abnormalities are more commonly seen in women over the age of 35, as egg quality declines," says Iris Insogna, MD, a reproductive endocrinologist and fertility specialist at Columbia University Fertility Center in New York City. You can have this test after nine weeks of pregnancy.
Integrated screening (sequential screening). There are two phases to this test. The first part happens between weeks 10 and 13 of your pregnancy. You'll get an ultrasound looking at your baby's neck and blood tests. Then, a second blood sample at 15-22 weeks will check your baby's risk for Down syndrome and neural tube defects like spina bifida — a spinal cord and brain disorder.
Triple or quadruple screening test. This test checks your blood for hormones and proteins that come from your baby or your placenta, the organ that brings the growing baby oxygen and nutrients. The test can look for three different substances (triple screening) or four (quadruple screening). Certain amounts of these substances mean your baby has a higher chance of having a birth defect or a genetic disease. This test happens in the second trimester, usually at 15 to 22 weeks.
Other Tests
If you get a positive result on a screening test, your doctor can use other tests to look for a problem.
Amniocentesis. Placing a thin needle in your belly, your doctor takes a sample of the fluid that surrounds your baby and checks it for genetic disorders or birth defects. It does carry some risk. About 1 in 300 to 500 women miscarry because of amniocentesis. Your doctor can tell you if it's important for you to have this test.
Chorionic villus sampling (CVS). The doctor takes a small sample of your placenta by putting a needle through your belly or a small tube up your vagina. They test the sample for Down syndrome and other genetic conditions. Only some high-risk mothers will need this test, usually if a previous child has a genetic condition or if screening indicates a risk of a genetic disorder. The procedure will tell you for sure if there's a problem, but like amniocentesis, it also comes with a risk of miscarriage. Talk to your doctor about whether you should have CVS.
What Do I Do Once I Have the Results?
Prenatal test results can help you make important health care decisions. But it's important to remember that many of them tell you it’s possible, but not certain, that your baby will be born with a disorder. No test is 100% accurate.
"It is important to review these results with your doctor so you understand the implications," Insogna says. "If there are any concerning findings on the early screening, you may be offered more definitive testing with an amniocentesis, for example."
A genetic counselor can also help you decide what to do after a positive result and what life will be like for your child if they have a disorder.
Questions for Your Doctor
If your doctor suggests prenatal testing, consider asking:
- Why do I need these tests?
- What will the results tell me? What will they not show?
- What happens if I don't get the test?
- What will I do with the results?
- How accurate are the tests?
- What are the risks?
- How long will it take to get the results?
- What does the test feel like?
- How much will it cost?
- Will my insurance cover it?
- Will anyone else (like my insurance company) have access to the results, especially of genetic tests?
- What will the results mean for my family?
- Can I decide not to get the results even if the test has already been done?
- Where do I get the tests done?
Takeaways
Prenatal tests, such as ultrasound and blood tests, offer information about the health of your baby. Genetic tests detect birth defects or chromosomal diseases before your baby's birth. Ask your doctor which of these tests you need based on your family health history and other risks. Make sure you understand the risks and benefits of each test your doctor recommends.
Prenatal Testing FAQs
Can my OB/GYN do a prenatal paternity test?
A paternity test confirms who the father of the baby is by collecting genetic material from the potential father and the fetus. Your OB/GYN or fertility doctor can do this test, but it's important to get counseling if you plan to have a paternity test, Insogna says. "One should be prepared for any possible answer and how that may affect one's feeling toward the pregnancy," she adds.
What is the least risky prenatal test?
Blood and urine tests are very safe prenatal tests. "An early ultrasound at 10-13 weeks is also a noninvasive and safe way to assess some markers of fetal health," Insogna says.
Is the baby affected during the prenatal testing?
Blood tests and ultrasound don't affect the growing baby. Amniocentesis and CVS carry a very small risk of miscarriage or needle injury to the baby.
Are there prenatal tests for Down syndrome?
Yes. Blood tests, ultrasound, amniocentesis, and CVS can test for Down syndrome and other genetic conditions.
