16 Essential Blood Tests during First Trimester of Pregnancy

Essential Blood Tests During First Trimester Of Pregnancy

The very first step in pregnancy is a blood test to confirm the good news! After that, you may have to go through some blood tests to verify the levels of various components in the blood. In short, blood tests are a part of your first antennal visits.

Common First Trimester Blood Tests

Your doctor will suggest a few blood tests during your first prenatal visit. These tests are optional, but it is advisable to go for the tests as it gives the doctor an idea about your health. These blood tests may also highlight any potential problem that you may encounter during your pregnancy.

1. Blood Group

It is important for the doctor to determine your blood group in case you need a blood transfusion anytime during the pregnancy.

2. Rhesus (R) Factor

It is crucial for the doctor to determine if you are RhD positive or negative. If you are RhD positive, that means that a protein called D antigen is present on the surface of your red blood cells, whereas if you are RhD negative, then you don’t have the protein. In this case, your doctor may give you a shot of Rh immune globulin once during the pregnancy and another after the baby’s birth. This shot is particularly necessary if you are a Rh-negative mother carrying a Rh-positive baby (which the baby may have inherited from his/her father). In this case, if some of your baby’s blood enters your bloodstream, then your body will produce antibodies that will attack your baby’s red blood cells. To avoid this, your doctor may advise you to take immune globulin shot during the 28thweek of pregnancy.

3. Iron Levels

A blood test is also done to check your haemoglobin levels, which determines if you are iron deficient. During pregnancy, your body needs iron to produce enough haemoglobin that can carry oxygen to all parts of your body and the baby. Hence, if your blood test shows that you are iron deficient, then your doctor may give you iron supplement to make up for the deficiency.

4. Blood Sugar

Your doctor will be interested in checking your blood sugar through a blood test if you are overweight or if you have a history of diabetes. A blood test is done to determine if you have gestational diabetes.

5. Hepatitis B

Blood test helps the doctor to determine if you are a carrier or Hepatitis B. Now, this is critical because if your baby gets Hepatitis B from you, it may cause severe damage to her liver. In this scenario, the doctor will inject your baby with antibodies to protect her from Hepatitis B as soon as your baby is born.


It is vital that all expecting mothers do an HIV and AIDS tests. If HIV or AIDS virus is detected in a mother-to-be, then necessary steps can be taken to ensure that the same does not get transmitted to the baby.

7. Syphilis

Syphilis poses a health risk both to the mother and the baby in the rare event that the mother is infected. If tested positive, the mother may be recommenced anti-biotics to treat it.

Which Other Blood Tests Should Be Done?

You may have to take some additional tests during the first trimester of your pregnancy. They are as follows:

Other tests during pregnancy

1. Screening for Thyroid

During the first trimester of pregnancy, your doctor would want to determine your thyroid level. If you have hypothyroid or hyperthyroid, you will be kept under close monitoring throughout the pregnancy to ensure that your thyroid hormones stay under control as it is essential for the proper development of the baby.

2. Rubella (German measles)

Catching Rubella during pregnancy can hurt baby’s heart, sight and hearing. While most women develop immunity against German Measles as kids, either through vaccination or by contracting it during childhood, there may be ones who have never got it and are at risk of getting Rubella during pregnancy. They must be very careful and stay away from anyone who has measles. There are no medicines or injections at this stage to prevent Rubella.

3. Combined Screening Test

This is a combination of blood test and a nuchal translucency scan that is done towards the end of the first trimester to determine if the baby has any genetic abnormalities like Downs syndrome. This is done alongside your normal scan for more specific results.

4. Cytomegalovirus (CMV)

A blood test is done to check if a virus called CMV infects you. A mother infected with this virus can pass it on to the foetus, and it may have severe implications for the developing baby like hearing loss or mental retardation.

5. Hepatitis C

Hepatitis C blood test is optional and usually suggested if you believe that you may be infected by Hepatitis C. This test is only done if the doctors observe any symptoms of Hepatitis C from you.

6. Herpes Simplex Virus (HSV)

Herpes is a common and very painful infection that takes place in the mouth or the genital area. If not treated, it can cause brain damage in babies. Hence a blood test is done to check the presence of this infection in expecting mothers in case they show any symptoms of herpes.

7. Sickle Cell Disease and Thalassemia

Test for sickle cell disease or thalassemia is among the early pregnancy genetic blood test. Sickle cell disorder and thalassemia are two types of blood cell disorder can make you anaemic and can be passed on to your little one.

8. Toxoplasmosis

A toxoplasmosis infection may be passed on to the unborn baby f the mother contracts the infection in the first trimester, or in the first few week before conceiving, and it is this important to test for it. The infection may result in organ damage, miscarriage, or even stillbirth.

9. Screening for Vitamin D levels

A lack of the requisite amount of Vitamin D may cause weakened bones or abnormal growth in newborns, and increase the risk of complications such as preeclampsia in the mother-to-be. A test to determine the levels of vitamin D is thus often conducted in the first trimester.

What Blood Tests are Done at Home or the Collection Centre, Safely?

Big hospitals have their laboratories, and blood tests are done in these well-equipped labs. These days, many renowned labs offer to collect blood samples from home to save the patients from the trouble of moving out of bed when not well.

Pregnant Woman at doctors'

Many people worry about the safety of blood samples being collected from home and transported to the labs for the test. They assume that there are high chances of the results getting skewed in this scenario. But so far there is no definite evidence for the same.

Hence, all blood tests done at home or the collection centre are safe and accurate as long you chose a reputed laboratory.

Can You Request Additional Tests?

There are few conditions for which tests are not offered as a part of first-trimester screening blood test routine. In the following cases, you may request for an additional blood test.

Pregnant woman with cat

  • If you have a pet at home and you feel that you are in danger of being infected with toxoplasmosis which usually spreads through cat poop, soil or undercooked meat, then you must request your doctor to test you for the same. Toxoplasmosis can damage a developing baby or can be a cause of miscarriage. Hence, you must be careful.
  • If you are worried about being infected by Group B strep, then you can ask your doctor to test you for the same in late pregnancy, around the 37th week. An infected mother can pass it on to her child who may fall very ill soon after birth.
  • If you feel that you are at the risk of contracting Hepatitis C, then you should approach your doctor for a blood test. Your chances of contracting hepatitis C are high if you have injected drugs in the past, or have tattoos and body piercings.

Will You Be Tested for Blood Cell Disorders?

Yes, as mentioned before, you will be offered to test for blood cells disorder like sickle cells disorder and Thalassemia. These disorders can make you anaemic, and you may also end up passing it to your little one. Usually, all pregnant women who live in an area where these conditions are common are offered to take the blood cells disorder tests. If you have a history of anaemia, you may as well let your doctor know in advance and offer to take up the blood cells disorder tests.

Blood tests are a routine procedure for hospitals as it helps the doctor gage any underlying medical conditions that you may have. Many of the issues, when detected early, can help the mother and child as the appropriate medication can be started at the earliest.

Also Read: Quadruple Marker Test During Pregnancy