What Are Prenatal Tests?

Prenatal tests are screening or diagnostic tests that can help identify health problems that could affect pregnant women or their unborn babies. Some of these conditions can be treated, so it's important to find them as soon as possible.

Why Are Prenatal Tests Done?

Prenatal tests are given in the first, second, and third trimesters. In a mother, they can determine key things about her health that can affect her baby's health, such as:

• her blood type
• whether she has gestational diabetes, anemia, or other health conditions
• her immunity to some diseases
• whether she has a sexually transmitted disease (STD) or cervical cancer

In a developing child, prenatal tests can:

• identify treatable health problems that can affect the baby
• show characteristics of the baby, including size, sex, age, and position in the uterus
• help determine whether a baby might have a birth defect, genetic problem, or other condition

Some prenatal tests are screening tests that can only reveal the possibility of a problem. Other prenatal tests are diagnostic tests that can accurately find whether a fetus has a specific problem. A screening test sometimes is followed by a diagnostic test.

Although your health care provider (who may be your OB-GYN, family doctor, or a certified nurse-midwife) may recommend these tests, it's up to you to decide whether to have them.

Who Should Have Prenatal Tests?

Some prenatal tests are considered routine — that is, almost all pregnant women receiving prenatal care get them. They include things like checking urine (pee) levels for protein, sugar, or signs of infection.

Other non-routine tests are recommended only for some women, especially those with high-risk pregnancies. These may include women who:

• are age 35 or older
• are teens
• have had a premature baby
• have had a baby with a birth defect (especially heart or genetic problems)
• are carrying more than one baby
• have high blood pressure, diabetes, lupus, heart disease, kidney problems, cancer, an STD, asthma, or a seizure disorder
• have an ethnic background in which genetic disorders are common (or a partner who does)

What Else Should I Know?

Remember that tests are offered to you — it's your choice whether to have them.

To decide which tests are right for you, talk with your health care provider about why a test is recommended, its risks and benefits, and what the results can — and can't — tell you.

Questions to ask:

• How accurate is this test?
• What does it measure?
• What do you hope to learn from the test results?
• Is the procedure painful?
• Could it be dangerous to me or the baby?
• Do the potential benefits outweigh the risks?
• When will I get the results?
• What are my options if the results indicate a problem?
• What could happen if I don't have this test?
• How much will the test cost?
• Is the test covered by insurance?
• How should I prepare for the test?