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Screening tests in pregnancy - Your pregnancy and baby guide

Media last reviewed: 15 February 2018
Media review due: 15 February 2021

You'll be offered some screening tests during pregnancy to try to find any health conditions that could affect you or your baby.

The tests can help you make choices about further tests and care or treatment during your pregnancy or after your baby's born. All screening tests offered by the NHS are free.

What are screening tests?

Screening tests are used to find people at higher chance of a health problem.

This means they can get earlier, potentially more effective, treatment or make informed decisions about their health.

Screening tests are not perfect. Some people will be told that they or their baby have a higher chance of having a health condition when in fact they do not have the condition.

Also, a few people will be told that they or their baby have a lower chance of having a health condition when in fact they do have the condition.

What do screening tests involve?

The screening tests offered during pregnancy in England are either ultrasound scans or blood tests, or a combination of both.

Ultrasound scans may detect conditions such as spina bifida.

Blood tests can show whether you have a higher chance of inherited conditions such as sickle cell anaemia and thalassaemia, and whether you have infections like HIV, hepatitis B or syphilis.

Blood tests combined with scans can help find out how likely it is that the baby has Down's syndrome, Edwards' syndrome or Patau's syndrome.

What are the risks of screening tests?

Screening tests cannot harm you or the baby but it is important to consider carefully whether or not to have these tests.

Some screening tests in pregnancy can lead to difficult decisions for you.

For example, screening tests for Down's syndrome, Edwards' syndrome or Patau's syndrome can lead to difficult decisions about whether to have a diagnostic test, such as amniocentesis, that carries a chance of miscarriage.

A diagnostic test tells you for certain whether you or your baby has the condition.

If diagnostic tests show your baby has a condition, this can lead to a decision about whether you want to continue or end the pregnancy.

Having a further test or ending the pregnancy will always be your decision, and health professionals will support you whatever you decide.

It's up to you whether or not you choose to have screening tests in pregnancy.

When will I be offered screening?

Different screening tests are offered at different times during pregnancy.

The screening test for sickle cell and thalassaemia should be offered as early as possible before 10 weeks of pregnancy.

It's recommended that screening blood tests for HIV, hepatitis B and syphilis should happen as early as possible in pregnancy.

This is so you can be offered specialist care and treatment to protect your health and reduce the chance of your baby getting infected.

These blood tests should not be delayed until the first scan appointment.

You'll be offered screening for Down's syndrome, Edwards' syndrome and Patau's syndrome around the time of your dating scan, which happens when you're around 11 to 14 weeks pregnant.

You'll be offered screening to check your baby's development at a 20-week scan when you're around 18 to 21 weeks pregnant.

Will screening tests give me a definite answer?

This depends what the screening tests are looking for.

Yes

Screening tests for HIV, hepatitis B and syphilis are very accurate, and will tell for certain whether you have these infections.

If the test is positive, you'll be offered further tests and examinations by specialist doctors to find out the treatment you need.

No

Screening for Down's syndrome, Edwards' syndrome and Patau's syndrome cannot say for certain whether your baby has the condition. It tells you if your baby has a lower or higher chance of having the condition.

If your baby has a higher chance of a condition, you'll be offered a diagnostic test that gives a more definite "yes" or "no" answer.

Screening tests for sickle cell and thalassaemia will tell you for certain whether you're a carrier or have these conditions. They will not tell you whether or not your baby has the condition.

If you or the baby's father is a carrier or has the condition, you'll be offered diagnostic tests to find out if your baby is affected.

Do I have to have screening?

No – it's up to you whether or not to have a screening test. It's a personal choice that only you can make.

You can discuss each of the screening tests you're offered with your midwife or doctor and decide whether or not it's right for you.

Some of the screening tests you'll be offered are recommended by the NHS.

These include:

  • blood tests for infectious diseases 
  • eye screening if you have pre-existing diabetes (not gestational diabetes)
  • newborn screening tests

This is because the results from these tests can help make sure that you or your baby get urgent treatment for serious conditions.

What screening tests will I be offered in pregnancy?

Find out more about each of the different screening tests:

Some screening tests will also be offered to your baby after they're born:

Your midwife or GP should give you a booklet about antenatal and newborn screening called Screening tests for you and your baby.

Confidentiality

By law, everyone working in, or on behalf of, the NHS must respect your privacy and keep all information about you safe.

The NHS Constitution sets out how the NHS should handle your records to protect your privacy.

In addition, there are laws in place to ensure confidentiality is maintained. Screening records are only shared with staff who need to see them.

Sometimes information is used for audit research purposes to improve screening outcomes and services. Information about this will be provided when you're screened.

Some private companies also provide screening tests that you have to pay for. The NHS cannot guarantee the quality of private screening.

Find out more about private screening.

Media last reviewed: 5 April 2017
Media review due: 5 April 2020

Page last reviewed: 8 February 2018
Next review due: 8 February 2021