Prenatal testing can provide valuable information about your baby's health. Understand the risks and benefits, and how prenatal testing might affect prenatal care.
By Mayo Clinic Staff
Pregnancy is a time of great anticipation — and anxiety.
You might be wondering if you'll experience complications or if your baby will have health problems. Take comfort in the fact that most babies are born healthy. Still, you might want details about your baby's health beyond what your health care provider can observe.
Enter prenatal testing.
Prenatal testing includes both screening tests and diagnostic tests:
- Screening tests. Prenatal screening tests can identify whether your baby is more likely to have certain conditions — but they usually can't make a definitive diagnosis. General screening tests, such as blood tests and ultrasounds, are routine in most pregnancies. Specific screening tests, such as first and second trimester screening for abnormal chromosomes, also might be offered. Screening tests pose no risks for mother or baby.
- Diagnostic tests. If a screening test indicates a possible problem — or your age, family history or medical history puts you at increased risk of having a baby with a genetic problem — you might consider a more invasive prenatal diagnostic test. A diagnostic test is the only way to be sure of a diagnosis. Some diagnostic tests, such as chorionic villus sampling or amniocentesis, carry a slight risk of miscarriage.
Despite these clear definitions, recent changes in technology have blurred the line between traditional screening and diagnostic tests.
For example, a new blood test for Down syndrome is now available in some areas. The test analyzes fetal DNA circulating in a mother's bloodstream. If a traditional screening test indicates a high risk of Down syndrome, the new blood test can define the risk more clearly. Although it isn't considered a diagnostic test, a normal result might eliminate the need for more invasive diagnostic testing.
Prenatal screening tests for fetal abnormalities are optional. It's important to make an informed decision about prenatal testing, especially if you're screening for fetal conditions that can't be treated.
- What will you do with the test results? Normal results can ease your anxiety. However, if prenatal testing indicates that your baby might have a birth defect, you could be faced with wrenching decisions — such as whether to continue the pregnancy. On the other hand, you might welcome the opportunity to plan for your baby's care in advance.
- Will the information shape your prenatal care? Some prenatal tests detect problems that can be treated during pregnancy. In other cases, prenatal testing alerts your health care provider to a condition that requires immediate treatment after birth.
- How accurate are the results? Prenatal testing isn't perfect. The rate of false-negative and false-positive results varies from test to test.
- What are the risks? Weigh the risks of specific prenatal tests — such as anxiety, pain or possible miscarriage — against the value of knowing the results.
- What is the expense? Insurance coverage for prenatal testing varies. If the test you're considering isn't covered by your insurance plan, are you willing and able to cover the cost of the test on your own?
Prenatal testing can provide information that influences your prenatal care. Remember, though, some screening tests introduce the need for careful personal decisions. Ultimately, the decision to pursue prenatal testing is up to you.
If you're concerned about prenatal testing, discuss the risks and benefits with your health care provider. You might also meet with a genetic counselor for a more thorough evaluation.
A genetic counselor can help you understand:
- The odds of your baby developing a particular condition
- How the condition would impact your baby's life, including your baby's physical and mental development and quality of life
- Possible treatment options, either during pregnancy or after birth
Taking the time to evaluate your options will help you make the best decision for you and your baby.
Aug. 14, 2012
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- Screening for birth defects. American College of Obstetricians and Gynecologists. http://www.acog.org/~/media/For%20Patients/faq165.pdf?dmc=1&ts=20120430T1648141913. Accessed April 30, 2012.
- Diagnostic tests for birth defects. American College of Obstetricians and Gynecologists. http://www.acog.org/Resources_And_Publications/Patient_Education_Pamphlets/Files/Screening_Tests_for_Birth_Defects. Accessed April 30, 2012.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. May 21, 2012.