What are prenatal tests?

A prenatal diagnostic test is used to diagnose certain birth defects, such as Down syndrome, during pregnancy. Diagnostic tests are offered to women who have a positive prenatal screening test, are over 35 years of age, have had a previous child with a birth defect or have a family history of a genetic condition. Prenatal diagnostic tests involve a small risk of miscarriage. Chorionic villus sampling (CVS) and amniocentesis are two of the more common diagnostic tests offered in hospitals.

Depending on your condition or screening results, you may have additional tests performed. Additional prenatal diagnostic tests might include a fetal echocardiogram, a nonstress test or ultrasound.
William D. Knopf, MD
Cardiology (Cardiovascular Disease)
Tests are used during pregnancy to check your and your baby's health. At your first prenatal visit, your doctor will use tests to check for a number of things, such as:
  • Your blood type and Rh factor
  • Anemia Infections, such as toxoplasmosis and sexually transmitted infections (STIs), including hepatitis B, syphilis, chlamydia,
  • and HIV Signs that you are immune to rubella (German measles) and chicken pox.
Throughout your pregnancy, your doctor or midwife may suggest a number of other tests, too. Some tests are suggested for all women, such as screenings for gestational diabetes, Down syndrome, and HIV. Other tests might be offered based on your:
  • Age
  • Personal or family health history
  • Ethnic background
  • Results of routine tests
Some tests are screening tests. They detect risks for or signs of possible health problems in you or your baby. Based on screening test results, your doctor might suggest diagnostic tests. Diagnostic tests confirm or rule out health problems in you or your baby.

This answer is based upon source information from the National Women's Health Information Center.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.