Prenatal blood tests can help families learn how likely their baby is to have common birth defects, and they can assess your health during pregnancy. As part of routine prenatal care recommended by the American College of Obstetricians and Gynecologists, all women should have certain tests early in their pregnancies.
Riley at IU Health offers a complete set of prenatal diagnostic procedures, prenatal blood tests and prenatal ultrasounds to assess each pregnancy. During your visit, we share information about each option so you can decide which tests, if any, are right for your unique situation.
Also known as screening tests, prenatal blood tests can reveal information about your health that could affect your baby’s health. Early in your pregnancy, these tests will:
- Identify your blood type and Rh factor—an inherited protein in red blood cells that some women have
- Analyze complete blood count (CBC)
- Detect certain conditions such as anemia, hepatitis B and C and sexually-transmitted diseases
- Determine whether you have immunities to conditions such as rubella
During your first trimester of pregnancy, you may have other routine tests depending on your risk factors for certain pregnancy complications such as gestational diabetes and preeclampsia—a form of high blood pressure.
Some prenatal blood tests predict your baby’s health by analyzing fetal biochemical or DNA fragments, which are present in your blood. These tests do not diagnose a fetal condition, but they can identify a risk for some disorders and genetic conditions. They can also alert physicians that further tests should be considered.
The gestational age of your pregnancy and your risk factors, such as your age and the family history of both parents, determine which of these screening options are right for you, including:
- Cell-free fetal DNA testing at or after 9-10 weeks gestation. This test screens for chromosomal conditions such as down syndrome, trisomy 18 and trisomy 13.
- Maternal serum AFP screening at 15-22 weeks to determine the risk of open neural defects such as spina bifida
Prenatal blood tests pose no risk to your pregnancy. They do, however, have a small chance of falsely raising a concern (false positive) or failing to detect a genetic condition when there is one (false negative).
Your physician may recommend more invasive diagnostic tests such as amniocentesis or chorionic villus sampling if you or your partner has certain risk factors or your screening test results signal further testing is needed.
Key Points to Remember
Key Points to Remember
- Some prenatal blood tests assess your health, while others analyze your baby’s risk of having certain conditions.
- The first prenatal tests expectant mothers have are aimed at screening them for health conditions that can affect their pregnancy or the health of their unborn babies.
- The mother's age and the family history of both parents are among the factors that decide whether to test for possible fetal health problems.
- Screening tests for your baby must be done at certain gestational ages to measure the risk of possible disorders or conditions.
- Although they pose no risk to a pregnancy, prenatal blood tests can raise an unnecessary concern or fail to detect a health condition when there is one.
Support Services & Resources
Support Services & Resources
These valuable resources can help expectant parents become more informed about prenatal tests such as amniocentesis.
We offer a broad range of supportive services to make life better for families who choose us for their children's care.
This organization for physicians has information for patients about screening and diagnostic tests that may be performed during pregnancy.
This U.S. government website publishes information about many types of health conditions, tests and treatments, and includes a description of prenatal testing.
Visit this National Library of Medicine website to get information about genetic conditions and learn about various types of genetic tests.