Infectious diseases
Updated 11 August 2025
Applies to England
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This publication is available at https://www.gov.uk/government/publications/screening-tests-for-you-and-your-baby/infectious-diseases
This short animation explains why screening for infectious diseases in pregnancy is important.
Infectious diseases in pregnancy video
Screening for infectious diseases is recommended by the NHS.
1. Purpose of screening
We offer screening to find out if you have hepatitis B, HIV (human immunodeficiency virus) or syphilis. Women who are living with HIV, hepatitis B and/or syphilis need early specialist appointments. This is to plan their care in pregnancy.
Women who already know they are living with HIV, have hepatitis B, or have had treatment for syphilis in the past are still advised to be tested in every pregnancy. Please inform your midwife or healthcare professional if you have a previous diagnosis for any of these infections.
2. About these conditions
Hepatitis B, HIV and syphilis are passed on in blood and body fluids. This can be through sexual contact or sharing infected needles and equipment used for intravenous drugs. These viruses can also be passed on to the baby during pregnancy and/or birth.
2.1 Hepatitis B
Hepatitis B virus affects the liver. It can cause acute (immediate) and chronic (long-term) ill health. Babies who become infected at birth or during the first year of life have a 9 in 10 (90%) chance of developing chronic hepatitis B infection. This can lead to illnesses such as liver problems and cancers. The risk is significantly reduced to around 1 in 10 (10%) if the baby completes the full course of vaccinations.
2.2 HIV
HIV weakens the immune system, making it difficult to fight off infections. If untreated, it can be passed on to the baby in pregnancy, when giving birth or by breastfeeding. Treatment in pregnancy greatly reduces the chance of passing on HIV to a baby from 1 in 4 (25%) to less than 4 in 1,000 (0.4%). Treatment can also be given to the baby at birth to reduce the chance of the baby becoming infected.
2.3 Syphilis
Syphilis is an infection passed on through unprotected sexual contact. It can be passed on to the baby during pregnancy. If it is not treated in pregnancy, it can result in serious health and developmental problems for the baby. It can also cause miscarriage or stillbirth. Treatment in pregnancy can reduce the chance of the baby being infected.
3. The screening test
Blood is taken from your vein, usually in your arm.
A blood sample being taken
A small amount of this blood is stored in the laboratory. This can be used for tests if you show signs of other infections or rashes during your pregnancy.
4. Safety of the test
There are no risks associated with the test.
5. Screening is your choice
These tests are strongly recommended. They can protect your health in pregnancy and allow for prompt treatment and care. They also greatly reduce any chance of passing the infection on to your baby, partner or other family members.
6. Not having the test
If you decide not to be tested, you will be reoffered screening later in pregnancy, ideally by 20 weeks. You will be encouraged to discuss your concerns around testing with a member of the maternity screening team or sexual health team.
If you decide not to have screening for infectious diseases, we will record this. This is because NHS England wants to check how many people decide not to be screened. Understanding this will help improve pregnancy outcomes for both mothers and babies.
7. Negative result
A negative result means you were negative when you had your blood sample taken. You can still become infected at any point during your pregnancy.
Speak to your midwife or GP as soon as possible if you develop symptoms or if you think you need repeat testing.
You and your partner can be tested at any time and can access local sexual health services at any point. We recommend repeat testing if you:
- change your sexual partner
- your partner is sexually active with other people
- have a partner who is diagnosed with a sexually transmitted infection (STI)
- inject recreational drugs
- are a sex worker
8. Positive result
8.1 HIV
If you are living with HIV, treatment and specialist healthcare can greatly reduce the chance of it being passed on to your baby. It is usually advised to avoid breastfeeding. However, this can be supported if you are receiving good HIV treatment. You should discuss this with your healthcare team.
8.2 Hepatitis B
If you are living with hepatitis B it is important for specialist teams to check your health before and after the birth. Your partner, any other children and close family members are also advised to have testing and vaccination.
Your baby will come into contact with your blood when they are born. Because of this, the virus could be passed onto them.
It is therefore very important that your baby has all 6 recommended hepatitis B vaccinations at the correct times. This will reduce the risk of your baby having chronic hepatitis B from a 9 in 10 chance (90%) to a 1 in 10 chance (10%). Ask your GP, practice nurse or health visitor if any of these do not happen. Vaccinations should take place:
- within 24 hours of birth
- at 4 weeks of age
- at 8, 12 and 16 weeks of age (part of routine childhood immunisation schedule)
- at 18 months of age
Your baby may also need a blood test and an injection of antibodies (hepatitis B immunoglobin) with their first vaccination.
Your baby will also have a blood test at their final vaccination. This takes place between 12 and 18 months of age. It is to check if infection was avoided.
8.3 Syphilis
If you have syphilis, referral to a specialist sexual health team is needed. Treatment is usually with a course of antibiotics. These are safe for your baby if you take them. The team will also offer to test your partner to see if they need treatment.
If you need treatment for syphilis during your pregnancy, your baby will need an examination and blood tests after birth. They may also need antibiotics. Your baby will require a follow up appointment at 3 months of age. This is to make sure that they have no signs of infection.
9. Getting my results
If your result is negative your midwife will discuss it with you. This will happen at or before your next antenatal appointment at about 16 weeks. It will also be recorded in your notes.
If you are screen positive for HIV, hepatitis B or syphilis, a specialist midwife will contact you. They will arrange an appointment within 5 days of the result being available. They will discuss the result, carry out further tests and plan your care with you.
Find more information and details of support groups on NHS.UK.