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Common Tests During Pregnancy

At your first prenatal visit your doctor will recommend that you complete many tests to see if there are any risks to yourself or the baby. Many of these tests are offered to all pregnant women. There are many tests that can be done during pregnancy to check on the baby and yourself. Your doctor will offer the tests that are most appropriate for you and your baby. The tests explained here are routine for the first prenatal visit, they do not mean that the doctor suspects you may have any of these conditions; they are done to screen all women and prevent complications.

Blood Work

Your doctor will send you to get blood taken and your blood will be sent to a lab to be screened for many different things. Once the tests results are back the doctor will discuss with you if he has any concerns. This section talks about the routine tests that are done during your first visit to the doctor. If you have any concerns or questions about these tests you should contact the health unit or your doctor. (ex of photos needed – taken off of google, can not actually use)

Each person’s blood has what is called a type. Your blood is made up of cells, these cells are red and each cell may or may not have what is called an antigen on it. There are two types of antigens that can be attached to your red blood cells (A or B). On your red blood cell you may have either A, B, both, or none. If your blood cell has an A antigen you are blood type A. If your blood cells have B antigens you are blood type B. If your blood cells has both A and B antigens you are blood type AB. If your blood cell has no antigens you are blood type O. Type O blood is the most common type of blood in North America.

Your blood also may contain a protein called Rhesus factor or Rh factor. Most people have Rh factor in their blood and therefore are considered Rh positive. About 15% of people do not have Rh factor in their blood and therefore are Rh negative.

The doctor will order blood work to find out which type of blood you have and if you are Rh positive or negative. The doctor needs to know this for two reasons. In the rare event that you should need blood the doctor needs to know what kind of blood you have in order to give you the correct type of donor blood. The doctor also needs to know your blood type as problems can arise if you are Rh negative and your baby is Rh positive. If you are found to be Rh negative the doctor will simply give you a needle of Rh-immune globulin (RhIg). RhIg is a medication to stop your blood from making antibodies and harming your baby. This is given between the 28th-32nd week of pregnancy or at any time in which bleeding has or may have occurred.

This test will also tell your doctor if there are any other antibodies in your blood which show any conditions or infections you have or have had in the past.


Hemoglobin is a protein found in the blood on our red blood cells. This protein carries oxygen from our lungs to the rest of our body and to your baby. The doctor does this blood test to find out how much oxygen your blood is able to carry. If your blood does not have enough hemoglobin you may have anemia. This means that your body is not getting enough oxygen. Anemia is very common in pregnant women because your body is using extra iron at this time and iron is needed to make hemoglobin. Because our bodies do not create iron on their own we must get it from what we eat, or our diet. If the blood test reveals that you have anemia your doctor may prescribe iron to help boost your hemoglobin levels and therefore the amount of oxygen you are able to carry.

Hep B Surface Antigen

This blood test will show if you have ever been exposed to the hepatitis B virus. If you have been vaccinated for hepatitis B you should be immune, but if you have not had your vaccine you are at risk for infection. If you have not had your vaccine your doctor will discuss the risks and benefits of the vaccine with you. This is an important test because if you have this virus you could pass it to your baby. This virus can also be passed to other people by blood and bodily fluids. Viruses cannot be cured and people who get hepatitis B will go on to carry the disease for life. If it is found that you have hepatitis B your baby will be treated as soon as possible after birth to prevent them from getting the virus.

Human Immunodeficiency Virus (HIV)

All pregnant women are offered to be screened for HIV. This test is needed because a mother with HIV can pass it to her baby when pregnant, during birth, or while breastfeeding. HIV can be passed through vaginal fluids, blood, and breast milk. There is no cure for HIV and therefore if you are found to have HIV the doctor will take extra care to prevent the baby from being exposed to the virus. The risk of the baby having HIV can be reduced to about 1% with proper treatment for the mother and the baby.


Syphilis is a sexually transmitted infection (STI) passed through the blood. This STI can be passed during birth and infect your baby. Your blood work will show if you have syphilis and your doctor can then treat you with antibiotics.

Rubella (German measles) and Varicella (Chicken Pox)

Rubella and Varicella (chicken pox) are viruses that are covered with the MMR (measles, mumps, rubella) and Varicella vaccines given to children. If you have received these vaccines as a child you should be immune. If you have not had the chicken pox vaccine but have had the chicken pox virus you are also thought to be immune. Your blood work will confirm if you are immune or not. Being immune means that if you come into contact MMR or chicken pox you should not become sick. If you are not immune and come into contact with the virus you may become sick. The MMR vaccine contains a live virus and because of this it is not safe to give to pregnant women. Because both of these viruses can be harmful to a growing fetus it is best to know that you are immune before you become pregnant. If you are not immune to MMR or varicella your doctor will discuss your options with you.

Pap test

Your doctor may complete a pap test during your first visit if you are due for one. In Canada women aged 21 and older should receive yearly pap tests if they have ever had sex. During this test your doctor will take a scraping of cells from your cervix. These cells will be looked at to see if they have any changes that may lead to cancer or show current cancer.

Urine Test

Your doctor will order a urine test to check your sugar and protein levels which is a way of testing for diabetes and other conditions. This will also be tested to ensure you do not have a urinary tract infection (UTI) which could harm your baby. If you do have a UTI the doctor can treat this with antibiotics. Without treatment for a UTI you are at risk for preterm labour which can be a danger for yourself and the baby.


Every pregnant woman should have at least one ultrasound after about 18 weeks. This is a test used to view the baby and take pictures of him/her inside of your uterus. An ultrasound is able to take pictures by making sound waves which create an image. Your doctor will inform you on how you should prepare for the test. For some of the tests you must have a full bladder. This means you must drink lots of water before the test and hold it in your bladder until the test is over. This helps the sound waves travel so that the picture is very clear. During the test a gel will be put on your stomach and a tool called a transducer will be moved around to see the baby from many angles. This should take about 30 minutes. The first ultrasound is used to confirm the baby’s due date and check on the baby’s well-being. This test can also be used for many other reasons such as checking for abnormalities, seeing where the placenta is, seeing what position the baby is in, checking the baby’s growth, and checking the level of amniotic fluid. You may also be able to hear the baby’s heart and determine their sex with this test. For more information on the ultrasound visit this webpage.

Genetic Testing

HNHU_DNA_MoleculeGenetic testing is done to screen for hereditary conditions such as:

  1. Downs Syndrome
  2. Trisomy 18
  3. Open Spina Bifida

A hereditary condition is one that is passed to the baby through mom or dad’s DNA / genes.

90% of pregnant mothers give birth to healthy babies but there is always a risk of your baby having a genetic abnormality. You and your doctor will discuss the benefits and risks of these tests.

This testing is done with blood tests, ultrasounds, or both, depending on what you have in your community. The blood test done to show if your baby is at risk for a genetic condition is called maternal serum screening and it looks for substances in the blood called “markers”. The ultrasound is used for a nuchal translucency test which this looks at the layer of fluid at the back of the baby’s neck. If this layer is thicker than average it may mean your baby is at risk for Down’s syndrome. In the event that any of these tests reveal your baby is at risk for a genetic condition you and your doctor will discuss the risks and benefits of further, more accurate, testing. For more information on these conditions and their tests visit:\