What are the routine Tests and Screening During Pregnancy

Tests and screenings during pregnancy is an important part of your prenatal care. These tests help your health care provider find problems that might affect your pregnancy.

Some tests are done for all pregnant women, and some are optional. Most of the tests and screenings do not pose any risks for you or your baby. You may need additional testing if any routine tests indicate a problem.

Tests and screenings done in early pregnancy

Some tests and screenings you can expect to have in early pregnancy include:

• Blood tests, such as:
  • Complete blood count (CBC). This test is done to check your red and white blood cells. It can help identify a risk for anemia, infection, or bleeding.
  • Blood typing. This test determines your blood type as well as whether you have a certain protein in your red blood cells (Rh factor). If you do not have this protein (Rh negative) and your baby does have it (Rh positive), your body could make antibodies to the Rh factor. This could be dangerous to your baby’s health.
  • Tests to check for diseases that can cause birth defects or can be passed to your baby, such as:
    • German measles (rubella). The test indicates whether you are immune to rubella.
    • Hepatitis B and C. All women are tested for hepatitis B. You may also be tested for hepatitis C if you have risk factors for the condition.
    • Zika virus infection. You may have a blood or urine test to check for this infection if you or your partner has traveled to an area where the virus occurs.
• Urine testing. A urine sample can be tested for diabetes, protein in your urine, and signs of infection.
• Testing for sexually transmitted infections (STIs), such as HIV, syphilis, and chlamydia.
• Testing for tuberculosis. You may have this skin test if you are at risk for tuberculosis.
• Fetal ultrasound. This is an imaging study of your developing baby. It is done using sound waves and a computer. This test may be done at 11–14 weeks to confirm your pregnancy and help determine your due date.

Tests and screenings done later in pregnancy

Certain tests are done for the first time during later pregnancy. In addition, some of the tests that were done in early pregnancy are repeated at this time. Some common tests you can expect to have later in pregnancy include:

• Rh antibody testing. If you are Rh negative, you will have a blood test at about 28 weeks of pregnancy to see if you are producing Rh antibodies. If you have not started to make antibodies, you will be given an injection to prevent you from making antibodies for the rest of your pregnancy.
• Glucose screening. This tests your blood sugar to find out whether you are developing the type of diabetes that occurs during pregnancy (gestational diabetes). You may have this screening earlier if you have risk factors for diabetes.
• Screening for group B streptococcus (GBS). GBS is a type of bacteria that may live in your rectum or vagina. You may have GBS without any symptoms. GBS can spread to your baby during birth. This test involves doing a rectal and vaginal swab at 35–37 weeks of pregnancy. If testing is positive for GBS, you may be treated with antibiotic medicine.
• CBC to check for anemia and blood-clotting ability.
• Urine tests to check for protein, which can be a sign of a condition called preeclampsia.
• Fetal ultrasound. This may be repeated at 16–20 weeks to check how your baby is growing and developing.

Screening for birth defects

Some birth defects are caused by abnormal genes passed down through families. Early in your pregnancy, tests can be done to find out if your baby is at risk for a genetic disorder. This testing is optional. The type of testing recommended for you will depend on your family and medical history, your ethnicity, and your age. Testing may include:

• Screening tests. These tests may include an ultrasound, blood tests, or a combination of both. The blood tests are used to check for abnormal genes, and the ultrasound is done to look for early birth defects.
• Carrier screening. This test involves checking the blood or saliva of both parents to see if they carry abnormal genes that could be passed down to a baby.

If genetic screening shows that your baby is at risk for a genetic defect, additional diagnostic testing may be recommended, such as:

• Amniocentesis. This involves testing a sample of fluid from your womb (amniotic fluid).
• Chorionic villus sampling. In this test, a sample of cells from your placenta is checked for abnormal cells.

Unlike other tests done during pregnancy, diagnostic testing does have some risk for your pregnancy. Talk to your health care provider about the risks and benefits of genetic testing.

Where to find more information

• American Pregnancy Association: americanpregnancy.org/prenatal-testing  
• Office on Women’s Health: womenshealth.gov/pregnancy  
• March of Dimes: marchofdimes.org/pregnancy  

Questions to ask your health care provider

• What routine tests are recommended for me?
• When and how will these tests be done?
• When will I get the results of routine tests?
• What do the results of these tests mean for me or my baby?
• Do you recommend any genetic screening tests? Which ones?
• Should I see a genetic counselor before having genetic screening?

Summary

• Having tests and screenings during pregnancy is an important part of your prenatal care.
• In early pregnancy, testing may be done to check blood type, Rh status, and risks for various conditions that can affect your baby.
• Fetal ultrasound may be done in early pregnancy to confirm a pregnancy and later to look for any birth defects.
• Later in pregnancy, tests may include screening for GBS and gestational diabetes.
• Genetic testing is optional. Consider talking to a genetic counselor about this testing.