Blood tests during pregnancy

During pregnancy, you’ll be offered blood tests to help protect your health and the health of your baby. Blood tests are an important part of your care during pregnancy.

Benefits of having blood tests in pregnancy

Having these tests could help you make decisions about your care and the care of your baby, both before and after birth.

It’s your choice whether to have blood tests or not. Your decision won’t affect the quality of your care.

When will I have blood tests?

Most of the tests can usually be done at one time, and the midwife will usually take blood from your arm at one of your first visits.

Some tests may be repeated routinely later in your pregnancy. This will be discussed with you.

What will my blood be tested for?

Your blood will be tested for:

  • full blood count, blood group and Rhesus status (positive or negative)
  • sickle cell and thalassaemia
  • infectious diseases (hepatitis B, syphilis and HIV)
  • Down’s syndrome
  • Edwards’ syndrome
  • Patau’s syndrome

Full blood count, blood group and Rhesus status

During your pregnancy you’ll be offered a blood test to:

  • look at the red cells, white cells and platelets in your blood
  • find out your blood group (A, B, O or AB)
  • find out if you’re Rhesus (RhD) positive or RhD negative

More about blood count, blood group and Rhesus status

Sickle cell and thalassaemia

Sickle cell and thalassaemia are serious, inherited blood disorders that are passed on from parents to children through altered haemoglobin genes.

People who have these conditions will need specialist care throughout their lives.

Learn more about screening for sickle cell and thalassaemia

Infectious diseases

You’ll be offered a blood test for infectious diseases that can affect you and your baby, such as hepatitis B, syphilis and HIV.

These conditions are screened for because simple treatments can reduce the risks to you and your baby.

Read more about screening for infectious diseases

Down’s syndrome

In the UK, around 1 baby in every 700 born has Down’s syndrome. It’s the most common chromosomal condition.

You may choose to have tests during pregnancy to find out how likely it is your baby might have Down’s syndrome. This will either be a blood test or a combined blood test and scan.

Learn more about screening for Down’s syndrome

Edwards’ syndrome

In the UK, around 1 baby in every 5000 births has Edwards’ syndrome. It’s the second most common chromosomal condition.

You may choose to have tests during pregnancy which can help to find out how likely it is your baby might have Edwards’ syndrome. This will either be a blood test or a combined blood test and scan.

Read more about screening for Edwards’ syndrome

Patau’s syndrome

In the UK, around 1 baby in every 16,000 births has Patau’s syndrome.

You may choose to have tests during pregnancy which can help to find out how likely it is your baby might have Patau’s syndrome. This will either be a blood test or a combined blood test and scan.

Learn more about screening for Patau’s syndrome

Blood test results

You’ll usually be able to get your test results at your next clinic visit. All results are confidential.

Occasionally technical problems can occur and you’ll be asked to have another sample taken. Some tests are also routinely repeated later in pregnancy.

If further investigation is needed, you’ll be contacted as soon as possible and given advice and care.

Your options following a high chance result

If you get a higher-chance screening result for Down’s syndrome, Edwards’ syndrome or Patau’s syndrome, you can choose to have a further screening test (known as NIPT, which stands for non-invasive prenatal testing), a diagnostic test, or have no further tests.

What happens to your blood samples after testing is complete

Any of your leftover blood samples will be stored in the laboratory for at least 12 months. This is so they can be used in the future if any test results need to be checked.

Your leftover blood samples and other screening results may be used anonymously for other monitoring, laboratory, education and training purposes. This is to help improve the quality of patient care. If this happens your personal details will be removed.

If your samples are going to be used in research that identifies you, you will be contacted first. Samples that are identifiable as yours will never be used without your consent.

If you do not want your stored blood samples to be used for research, please ask the midwife to write ‘no research’ in the comments box on the request form.

You have rights in relation to the access and the use of your personal health information.

Learn more about privacy and confidentiality when using the NHS

What happens to your information after screening

Your personal health information will be kept private. This means it’s only shared with staff involved in your care. Processes are reviewed regularly to make sure you’re offered the best service possible.

You have rights in relation to the access and the use of your personal health information.

Learn more about privacy and confidentiality when using the NHS

Read more about data protection and the NHS

The results of some pregnancy screening tests are shared with Public Health Scotland, which is part of the NHS. Public Health Scotland uses the information to support ongoing monitoring and improvement of pregnancy screening.

Read more about PHS

Congenital and rare condition register

Babies with some of the conditions that are screened for in pregnancy are included in the secure congenital and rare condition (CARDRISS) register. The register is maintained by Public Health Scotland.

It monitors how many babies have these conditions. It’s also used to support the planning and improvement of health, care, and other public services.

Read more about CARDRISS

Last updated:
23 January 2023

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