Screening for infectious diseases

During your pregnancy you'll be offered a blood test to screen for infections that can affect you and your baby, such as hepatitis B, syphilis, and human immunodeficiency virus (HIV).

Why will I be screened for these conditions?

You'll be screened for these conditions because simple treatments can reduce the chances of you and your baby being affected by infectious diseases.

Hepatitis B

Hepatitis B is caused by a virus that can be passed from mother to baby during birth. The virus can cause serious liver disease, but women carrying hepatitis B may have no signs of infection. Without a test, they wouldn't know they’re infected.

Without immunisation, many babies born to mothers who are infected with hepatitis B will become infected themselves.

If the test shows you’re infected with hepatitis B, you’ll be offered specialist treatment.

Your baby will be immunised against hepatitis B at birth. This will usually stop them getting hepatitis B and protect them from serious liver disease.

Read more about hepatitis B 

Read more about the hepatitis B vaccine


People can have syphilis without realising it. You'll be tested for syphilis because if it isn't treated it can damage the health of you and your baby. Syphilis is passed on through sex, and it can be treated quickly and simply with antibiotics.

If the blood test shows you might have syphilis, you'll be offered a second test to confirm the results.

Read more about syphilis 

Human immunodeficiency virus (HIV)

HIV is the virus that causes acquired immunodeficiency syndrome (AIDS). Over time, HIV damages the immune system and destroys the body’s defenses against infection and disease.

A woman who has HIV can pass the infection to her baby during pregnancy, birth, or breastfeeding. Like hepatitis B and syphilis, women with HIV may not know they’re infected until they have a test, as it can take years for HIV to make someone unwell.

If the test shows you might have HIV, you'll be offered a second test to confirm the results.

If the test shows that you are HIV positive, specialists will offer you:

  • antiviral medicines to keep you healthy and greatly reduce the chance of you passing HIV to your baby
  • advice about the safest ways to deliver and feed your baby
  • advice about medicines your baby can have after they’re born to help protect against HIV

Medication to improve your own health can also be started if needed.

HIV cannot be cured, but with treatment, people with HIV can usually expect to live a full and healthy life.

More about HIV

HIV and insurance policies

Having a blood test for HIV does not affect your current or future life insurance policies, but if a health condition is found it could affect your insurance.

You might wish to check any policies you have for further details. It’s still recommended that you take the test.

Rash in pregnancy

Any illness where you have a fever and a rash may be due to you having an infectious disease that could harm your unborn baby.

Some infectious diseases to be aware of include:

  • chickenpox
  • measles
  • rubella (german measles)
  • mumps

Non-urgent advice: Phone your midwife or GP if you:

  • have a rash
  • come into contact with someone who may have an infectious disease

You should avoid any antenatal clinic, maternity setting, or other pregnant women until you've been assessed.

You may be offered tests to find out if you have an infectious disease. The healthcare professional that assesses you will need to know:

  • how many weeks pregnant you are
  • the date you first developed the rash
  • a description of the rash - for example, if the rash is raised, bumpy, or has blisters filled with fluid
  • what infections you've had in the past, for example chickenpox or measles
  • when you had contact with the person who may have an infectious disease
  • what vaccinations you've previously had

Test results

Your test results will usually be available at your next clinic visit.

If any issues are found, your healthcare team will contact you as soon as possible and you'll receive advice and care.

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

Last updated:
23 January 2023

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