Screening for sickle cell and beta thalassaemia

Carrier screening during pregnancy

Many of the people we talked to discovered they were a carrier of sickle cell or beta thalassaemia during pregnancy. The NHS Screening Programme has been introducing a programme of antenatal screening for these conditions. All women are now offered screening for beta thalassaemia as part of their routine antenatal tests. Those at high risk of being a sickle cell carrier will also be offered a screening test. Ideally, these tests should be done before 10 weeks of pregnancy. 

“All pregnant women are offered a test for thalassaemia but not all women are automatically offered a test for sickle cell disease. The screening offered depends on where you live. In areas where haemoglobin diseases are more common, you will be offered a blood test for sickle cell disease. In areas where haemoglobin diseases are less common, a questionnaire is used to identify the baby’s mother and father’s family origins. If the questionnaire shows either parent may be a sickle cell carrier, a screening test is offered to the woman. You can ask to have the test even if your family origins do not suggest the baby would have a high chance of a haemoglobin disease.” (Screening tests for you and your baby – Public Health England July 2017)

If the test is positive the baby's father will also be offered a test.

The blood tests involve taking a blood sample which is then sent to the laboratory to be analysed. For most people the result shows that they are not carriers (this is also known as a 'negative' result), but a few will get a letter or phone call to tell them that they are a carrier of sickle cell or beta thalassaemia (which is called a 'positive' result). In some cases they may be told they carry another type of haemoglobin (or 'haemoglobin variant'), such as haemoglobin C, E, D or O Arab.

Some people we talked to saw screening as just another routine blood test in pregnancy and did not expect any bad news. Several felt they had not been fully informed or sufficiently prepared for the consequences of a 'positive' test result. A few people believed it was the law that they had to have the test, although in fact everyone has a right to say they don't want to be screened. Although it was clear some people we talked to had not been well informed about screening and carrier status, the NHS Screening Committee is working to ensure that in future everyone receives clear and consistent information and advice before and after screening and had produced a booklet Screening tests for you and your baby’ that should be given to all pregnant women by their midwife or GP.This includes information about screening for sickle cell and thalassaemia in early pregnancy.

Most people we talked to who were screened in pregnancy said that they were offered the test automatically (or did not realise they were having it), but a few were screened at their own request.

(See also 'Partner screening'.)

Occasionally people who already knew they were carriers were asked to have screening again when they became pregnant. For some people this was not a problem, but one woman was angry that she kept being asked to come back for more tests.

Last reviewed December 2018.

Last updated December 2018.



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