Medical Tests to Expect During Your Pregnancy

To ensure the health of you and your baby, your provider will order certain laboratory tests during your pregnancy. Together with your medical history, physical examinations, and possibly other tests (e.g. ultrasound and fetal non-stress test), the results of your laboratory workup will enable your provider to evaluate your health status more thoroughly. The following describes the significance of the tests your provider will order.

• Complete Blood Count (CBC) – Gives the number of red and white blood cells in your blood along with information about your blood’s hemoglobin content and other indicators. The CBC is a test for anemia and the presence of infection.
• ABO/Rh Typing – Determines your blood group and Rh type and is important early in pregnancy to evaluate the possibility of incompatibility between your blood and your baby’s blood.
• Antibody screen – Performed to detect substances your body may produce during your pregnancy if your blood is not compatible with your baby’s blood.
• Rubella antibody – Ordered to determine whether or not you have had or have been vaccinated against German measles.
• VDRL – Tests for syphylis.
• Toxoplasma antibodies – Toxoplasmosis is a blood disease hosted in cats and other animals. If you have had recent exposure to cats, you should let your provider know as he/she may wish to test for a recent infection.
• Triple Test – Screening test for neural tube defects (open spine) and Down’s Syndrome and may be performed during weeks 15 to 20 of your pregnancy.
• Human Immunodeficiency Virus (HIV) antibody – Tests your blood for the presence of antibodies to the AIDS virus.
• Hepatitis testing – Your provider may decide to order one or more of several hepatitis markers for the detection of a possible infection and the prevention of transmission to your baby.
• Urinalysis – Performed to detect urinary tract infections and the presence of protein in your urine. A urine sample will be needed at each of your prenatal visits.
• Glucose – Also called blood sugar tests, are typically done on a blood sample drawn one hour after drinking a measured amount of glucose solution as a screening test for gestational diabetes. These tests may be followed up with a glucose tolerance test for diagnosis. This test is generally done around 28 weeks gestation.
• Cytology screening – Also called a pap smear, should be part of your first prenatal visit as a screening to detect cervical cancer.
• Gonorrhea and Chlamydia – These cervical cultures will be taken at the time of your pap smear to detect the presence of infections that may adversely affect the outcome of your pregnancy.

Amniocentesis

An amniocentesis is a sampling of your amniotic fluid (the fluid surrounding your baby inside the placenta). Your doctor will use ultrasound guidance and insert a needle into your uterus and remove a small amount of amniotic fluid for testing. An amniocentesis may be performed between 15 and 18 weeks gestation if you are in a high risk category for genetic disorders or health problems in your fetus. Your fetus may be at higher risk for developmental problems or genetic disorders if you are over the age of 35, if you and/or the father of the baby have a history of genetic (inherited) disorders in your families, or other screening tests have shown possible health problems with your fetus. Most amniocentesis results are normal and even abnormal results don’t always mean that there is a problem with your baby. Amniocentesis can indicate certain genetic problems (such as Down Syndrome, Trisomy-18, or Trisomy-13) or it can indicate if the fetus has problems with his/her spine, lungs, and/or other areas of the body.

Cystic Fibrosis Carrier Screening

Cystic Fibrosis (CF) is an inherited disorder that causes patients to have high levels of sodium and chloride (salt) in their sweat. It also causes patients to have a thick, sticky mucous in the lungs which causes persistent coughing, wheezing, and frequent lung infections (including pneumonia). It can often affect a child’s ability to gain weight because CF causes very low amounts of pancreatic enzymes. Pancreatic enzymes are integral in breaking down food and extracting nutrients from food that are needed for growth. CF symptoms, such as the above, can be mild to severe. CF is a recessive disease, which means a person must get one defective gene from his/her mother and one defective gene from his/her father in order to have CF. A person who has one defective CF gene will not have CF but will be considered a CF carrier. CF Carrier Screening is when both parents are tested for abnormalities in their CF genes (there are two known CF genes). This can help parents to determine if their fetus needs to be tested as well. Even if both parents are CF carriers, that does not mean their fetus will have CF or even be a CF carrier. If both parents are CF Carriers then the baby has a 25% chance of inheriting one good gene from each parent, a 50% chance of inheriting one faulty gene and one good gene (meaning the baby is a CF carrier), and a 25% chance of inheriting both defective genes (thus having CF). CF patients and CF Carriers are more common amongst people of Northern or Western European descent, particularly people of Ashkenazi Jewish descent. Knowing your family history (particularly if you know of a relative who had or has CF or is a CF Carrier) and your ethnic background are important in deciding if CF Carrier Testing is important for your and your baby.

The percentage of CF gene changes found by the screening test are as follows:

• Ashkenazi Jewish people – 97%
• Non-Hispanic Caucasians – 90%
• African Americans – 69%
• Hispanic Americans – 57%
• Asian Americans – insufficient data