Laboratory Tests

The following tests are performed early in pregnancy and may not be done at the same prenatal care visit. Some of these tests are repeated later in pregnancy.

• Blood type and antibody screen: Your blood type can be A, B, AB or O. It can also be Rh positive or Rh negative. If your blood cells lack a protein called the Rh antigen, your blood is “Rh negative.” If your blood cells carry the Rh antigen, your blood is “Rh positive.” Problems can arise when the baby’s blood has the Rh antigen and yours does not, a condition called Rh incompatibility. Your body may make antibodies that attack the baby’s blood, which can cause the baby to have anemia. This condition requires special care during pregnancy.

• Hematocrit and hemoglobin: These tests check for anemia. If your hematocrit and hemoglobin levels are low, you may be advised to increase your iron intake.

• Rubella: Your blood will be checked for immunity to rubella (German measles). If you had this viral infection before or been immunized against it, you are not at risk for rubella infection.

• Glucose: The level of sugar in your blood is measured to test for gestational diabetes mellitus. For this test, you drink a sugar mixture. An hour later, a blood sample is taken from your arm and sent to a lab. This test is done early in pregnancy if you are at increased risk for gestational diabetes. If you are not at increased risk, you may have this test at 24 to 28 weeks of pregnancy. Women at very low risk for gestational diabetes may not need this screening test.

• Sexually transmitted diseases: You will be tested for certain STDs, including syphilis, chlamydia, HIV and hepatitis B.

• Urine: A urine test will be done to determine whether you have bacteria in your urine. If your test result is positive, you will need further testing.