Screening tests in pregnancy

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

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.

What screening tests will I be offered in pregnancy?

  • screening for infectious diseases (hepatitis B, HIV and syphilis)
  • screening for inherited conditions (sickle cell, thalassaemia and other haemoglobin disorders)
  • screening for Down's syndrome, Edwards' syndrome and Patau's syndrome
  • screening for 11 physical conditions (20-week scan)

NHS Choices has more information about the screening tests you will be offered, what they will involve and help and advice about the tests and the results.

Group B Strep information

Group B Streptococcus (Group B Strep, Strep B, Beta Strep, or GBS) is a type of bacteria which lives in the intestines, rectum and vagina of around 2-4 in every 10 women in the UK (20-40%). This is often referred to as ‘carrying’ or being ‘colonised with’ GBS.

Group B Strep is not a sexually transmitted disease. Most women carrying GBS will have no symptoms. Carrying GBS is not harmful to you, but it can affect your baby around the time of birth.

GBS can occasionally cause serious infection in young babies and, very rarely, during pregnancy before labour.

  • Group B Strep is one of the many bacteria that normally live in our bodies and which usually cause no harm
  • Testing for GBS is not routinely offered to all pregnant women in the UK
  • If you carry GBS, most of the time your baby will be born safely and will not develop an infection. However, it can rarely cause serious infection such as sepsis, pneumonia or meningitis
  • Most early-onset GBS infections (those developing in the first week of life) are preventable
  • If GBS is found in your urine, vagina or rectum (bowel) during your current pregnancy, or if you have previously had a baby affected by GBS infection, you should be offered antibiotics in labour to reduce the small risk of this infection to your baby
  • If GBS was found in a previous pregnancy and your baby was unaffected, you can have a specific swab test (known as the ECM test) to see whether you are carrying GBS when you are 35-37 weeks pregnant. If the test result is positive, you will be offered antibiotics in labour. If the ECM test result is negative at this point, then the risk of your baby developing early-onset GBS infection is low and you may choose not to have antibiotics
  • The risk of your baby becoming unwell with GBS infection is increased if your baby is born preterm, if you have a temperature while you are in labour, or if your waters break before you go into labour
  • If your newborn baby develops signs of GBS infection, they should be treated with antibiotics straight away.

Screening pregnant women for GBS is not recommended by the UK National Screening Committee because:

  • a woman may have a positive result a few weeks before labour and a negative result when she gives birth
  • GBS does not cause an infection in every baby- there is no way of telling which babies will be affected
  • screening may result in giving many women antibiotics when they do not need them
  • it is not known if the benefits of screening outweigh the harms for most of the population
  • the proportion of babies affected by disease in countries where screening is carried out is similar to that in the UK

If you experience a quick delivery and did not receive at least 4 hours of intravenous antibiotics, your baby will be deemed high risk and given a red hat to wear. 

For further information, advice and support please head to NHS Choices.