Blood Tests during Pregnancy

The moment you see those two lines on the pregnancy test, your entire life changes. A woman goes through so many changes from then – mentally, emotionally and of course physically. But the first thing a pregnant mother is concerned about is whether the baby is growing fine and is healthy. To answer these crucial questions, your gynaecologist will suggest that you get some routine blood tests done. Apart from the blood tests there will be other non-blood tests that will be needed to be done as you progress in your pregnancy.

Why Do You Need to Do Plenty of Blood Tests During Pregnancy?

It can be overwhelming to take so many tests during pregnancy especially if you are going through morning sickness or are very tired, but rest assured that these are important, normal and a routine procedure. There are many reasons why you will be asked to take blood tests during your pregnancy. The important ones are:

  • A blood test is done to confirm your blood group. It is also done to identify any infections or diseases you may have. The test also indicates if the foetus is at the risk of any abnormalities.
  • It throws light on your overall health and if there is a possibility of any issues later during your pregnancy.
  • Doctors check if you are Rh- positive or -negative through a blood test.

What Details Do Pregnancy Blood Test Results Show?

All blood tests are done to determine whether the foetus is growing well and is healthy. Pregnancy blood tests reveal if there are any problems or complications at present or if they may arise as the pregnancy progresses. Some important results that the blood tests confirm are:

  • The blood group and type of the mother
  • If there are any diseases like Rubella, Syphilis, Hepatitis B affecting the mother
  • If she has gestational diabetes or is suffering from any other infectious illnesses
  • If the foetus is healthy and growing well without any birth defects

Which Blood Test Will the Doctor Prescribe in First Appointment?


With that one prick during your first prenatal appointment, your doctor can gather a lot of information about your body and health.

Your first blood test looks for:

  • HCG levels in your bloodstream; this will help your gynaecologist to determine your due date since HCG levels increase as the pregnancy progresses.
  • Blood group and Rh factor test
  • Sexually Transmitted Diseases
  • Vitamin and iron deficiencies
  • Genetic risks like cysts or fibroids
  • Blood sugar levels

Blood Test in the First Trimester

The first trimester is the start of a wonderful journey into motherhood. You will be required to take good care of yourself and follow a healthy lifestyle. During your first antenatal checkup, your doctor will recommend certain tests to be done which will give more insight into your pregnancy and foetus. The 10-week blood test during pregnancy are:

1. Blood Group Test

This is simply to confirm which blood group you belong to i.e. A, B, AB or O.

2. Rhesus Factor Test

Once your blood group is confirmed, the next step is finding out your Rh type. This is done to determine whether you have the ‘D’ antigen on the surface of your red blood cells. In case you do, then you are Rh-positive and if you don’t, then you are Rh-negative. If your baby’s blood group is positive and so is yours, there isn’t any problem, but if your blood group is negative and that of your baby is positive, then your body may produce antibodies against your baby’s blood. This won’t affect the current pregnancy but may affect any future pregnancies. If the Rh types of the parents do not match, the doctor administers a shot of Rh immunoglobulin which will prevent the mother’s body from producing antigens now or even for future pregnancies.

3. Anaemia

A blood test can show whether you are anaemic, i.e. whether your haemoglobin levels are less, and if it is due to iron deficiency. If so, you will be prescribed iron supplements and advised to eat iron-rich foods. The test can also check your platelet count; increased white blood cells could be signs of an infection.

4. Rubella Test

The rubella virus if contracted during pregnancy can cause serious issues like miscarriage, preterm birth, stillbirths and also a variety of birth defects. This test checks the level antibodies if present, against the rubella virus in your blood and whether you are immune to it. Usually, women are immune to it, either because they were vaccinated or may have contracted rubella as a child. If you aren’t immune, then you will need to avoid exposure to anyone who has a Rubella virus infection or avoid travelling to places where the virus is prevalent. Do note that one can’t be vaccinated during pregnancy but only after conception.

5. HIV Testing

One of the most important and mandatory tests is for Human Immunodeficiency Virus that causes AIDS. If you do test positive, you can get treatment that will help you stay healthy and also reduce the chances of your baby becoming HIV positive.

6. Hepatitis B

Hepatitis B is a disease that affects the liver. Many women don’t even realise they have it and unknowingly pass it to their baby during labour. This blood test will check if you are a carrier of Hepatitis B. If so, your doctor will give your baby a Hepatitis B immunoglobulin injection and the first shot of Hepatitis B vaccine within 12 hours of the birth. Later on, your baby will need to take the second shot in the first month and third shot in the sixth month.

Blood Test in the Second Trimester

Typically, pregnant women see their doctors once a month for regular checkups. During your second trimester, apart from your routine checkup, there will be a few blood tests to be done as well. Some tests include:

1. Triple Screen Test

All pregnant women over the age of 35 will be offered the Triple screening test. This is also known as the “multiple marker screening” or “AFP plus”. The mother’s blood will be tested for:

  • AFP – a protein produced by the fetus.
  • HCG – a hormone that’s produced by the placenta.
  • Estriol – produced by both, the mother and the foetus.

These screening tests will check for abnormal levels of these substances. And later these results are considered along with other factors like mother’s age, health history, and ethnicity. The triple screen test can detect abnormalities in the foetus like Down syndrome, trisomy 18 syndrome and spina bifida.

2. Gestational Diabetes

Gestational Diabetes is diabetes that is caused due to high levels of sugar (glucose) in the blood. This usually happens during the 28th week of pregnancy and disappears once the baby is born. With a blood test, this can be determined and your doctor can treat you appropriately.

3. Cell-Free Foetal DNA Test

This is relatively a new test that is being administered. It helps to access the risk of the foetus having chromosomal abnormalities. The genetic material released from the placenta is called Cell-Free DNA, which can be detected in the mother’s blood. This will reveal if the foetus has any chromosomal disorders.

Blood Tests in the Third Trimester

The final trimester brings mixed emotions; you are almost there and in few months will be ready to see your little munchkin in your arms. The blood tests in pregnancy at 28 weeks are:

1. Glucose Testing

You will need to check your blood sugar levels again and determine if it’s normal. You will be given a sugary liquid and an hour later, a blood test is done. If sugar level is excessive, then an additional blood test for gestational diabetes will be done.

2. Hematocrit

To check iron deficiency. This blood test is done to check if the mother has lower levels of iron. If so, the doctor will prescribe iron supplements.

3. Sexually Transmitted Disease (STDs)

A blood test will be done to check STDs like HIV that can cause AIDS. Also, other diseases like syphilis will be checked for. A mother can have syphilis even without her knowing and pass it on to the baby during birth. In case she does test positive for the bacteria, she can be treated with antibiotics while pregnant and the baby can receive the antibiotic just after birth.

Is It Safe to Get Blood Tested at Home or a Collection Center?

Taking a blood test at home these days isn’t an issue. It is quite convenient especially if you are pregnant and don’t want to venture outside. But make sure you select a reputed diagnostic centre that has trained and experienced staff who know how to collect and store blood appropriately without being tampered or getting contaminated.

But heading out will give you a change of scene, especially during the last trimester; a trip to the diagnostic centre may just prove to be a welcome change.

The blood tests and other pregnancy-related tests are recommended to check the wellbeing of both the baby and the mother. Many of these tests are mandatory, and all pregnant women must take them. These blood tests are harmless and can give a clear picture of your baby’s growth and can medically intervene if any defects are discovered.