What Blood Tests Will You Have During Pregnancy?

May 26, 2021

When you’re pregnant, your doctor or midwife will want to conduct blood tests to check for various health concerns throughout your pregnancy. So, what type of blood tests will you have during your pregnancy, what exactly do these tests check for and why are they important for you and your baby’s health?

What is the first blood test?

The first and arguably most anticipated blood test you have in pregnancy is the one that confirms that you are in fact pregnant. This blood test checks for the level of beta-human chorionic gonadotropin in your body. This hormone is produced by cells of the developing pregnancy and is detectable in urine and blood.

Typically following a positive urine pregnancy test you will confirm the pregnancy via an HCG blood test. The level of the beta HCG hormone detected can help inform how many weeks pregnant you are, however determining your due date is best done based on your period dates and/or first ultrasound done by Dr Joseph Sgroi, a leading obstetrician, because the normal range for HCG varies widely.

The results of the test

In early pregnancy, you will have a blood test that provides myriad results. These results will form the baseline bloodwork for your pregnancy and include tests for blood group and antibodies, a full blood examination, immunity to varicella (chickenpox) and rubella, HIV/hepatitis/syphilis status, ferritin (iron) level, vitamin D level and thyroid function levels. Based on these results you may be asked to commence particular supplements or medications, such as iron or vitamin D, on top of your standard pregnancy multivitamin. Dr Joseph Sgroi and his staff will notify you of any additional supplementation you require.

The results also help Dr Joseph Sgroi to deliver the best possible care to you. For example, if you have a negative blood group you will require anti-D injections in pregnancy, or if there is evidence of blood antibodies you will be more closely monitored. The results also help keep you and the team involved with your care safe. For example, if you have hepatitis/HIV/syphilis you will need to take medication to protect you and your baby, and Dr Joseph Sgroi and his midwives will take appropriate precautions to keep themselves safe.

Aneuploidy screening

Dr Joseph Sgroi will also offer you screening for aneuploidy – or chromosomal abnormalities in pregnancy such as Down’s Syndrome. It is best to think about whether you actually wish to know the result of the test. Dr Joseph Sgroi will tell you that there are only two reasons for screening for chromosomal abnormalities.

These include if you would act on the result by medical interrupting (terminating) the pregnancy; or if it would better inform you of having a child with special needs. If your intent is not to medically interrupt a pregnancy or if you don’t wish to know then it is best not to have the test done.

Genetic carrier screening

Another test offered to you is Genetic Carrier Screening. This looks at commonly inherited conditions that can be passed on from parents to their offspring. Usually, these required two faulty genes, one coming from the maternal and the other from the paternal side.

Therefore, the fact that there isn’t a family history of genetically inherited conditions doesn’t mean there isn’t a chance of having a child born with one. Usually, this test is done as a saliva test. Genetic Conditions screening include Cystic Fibrosis, Spinal Muscular Atrophy and Fragile X.

Blood tests between 26 to 28 weeks

The next group of blood tests will be between 26 and 28 weeks and include repeat screening for full blood examination, blood group and antibodies and ferritin (iron) level. This blood test will also include gestational diabetes screening in the form of an oral glucose tolerance test, or OGTT. The OGTT identifies women who have developed gestational diabetes. The test takes two hours and requires three separate blood samples to be taken.

The test involves you fasting from midnight the night before, having a fasting blood test the following morning, drinking a concentrated glucose drink, and then having two further blood tests: one an hour after drinking the glucose drink and one an hour later still.

If one, two or all three blood test results are elevated the result is positive for gestational diabetes. Dr Joseph Sgroi’s Diabetic Nurse Educator Emily Fitz will notify you if you have Gestational Diabetes. If your result is normal then you won’t receive a notification.

Blood tests at 36 weeks

The final routine set of pathology tests in pregnancy is done at 36 weeks. This group of tests includes a full blood examination, ferritin level and a vaginal swab for a bacteria called Group B Streptococcus, or GBS. GBS is a common transient bacteria that can be present in the vagina. It is not an infection, nor is it sexually transmitted, rather it forms part of the normal bacteria that live in the body.

Adults can clear the bacteria themselves as they have strong immunity; babies who are born vaginally, however, can become colonised with GBS if it is present at birth and as babies have immature immunity, in rare circumstances (1-2 in 1000 live births) GBS can cause a neonatal infection. If GBS is detected, women will be administered IV antibiotics during labour to reduce the risk of transmission to the baby.


If you require any further information or have an enquiry, please contact us and we’ll get in touch with you shortly.

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