Screening for sickle cell and beta thalassaemia

Newborn screening after screening in pregnancy

Some parents who know during pregnancy they are carriers do not find out until after the baby is born whether he or she is affected by the condition. A sample of the baby's blood is taken using a 'blood spot test' (also known as the heel prick test), and can be tested for several conditions, including sickle cell disorders. These tests  are part of the routine tests carried out by the midwife in the first week after the baby is born. (Most cases of beta thalassaemia major can also be identified from newborn screening, but treatment is not required until the child is a few months old, and diagnosis may not be confirmed until later).

All women who know they are carriers, whether or not their partner has been screened, should be offered a diagnostic test (CVS or amniocentesis) during pregnancy to know for certain if the baby is affected. However, some choose not to know, especially if they feel sure they would not terminate the pregnancy. They may also be concerned about the small risk of miscarriage (around 1%) from having a diagnostic test (NHS Screening Programme 2014)

A few women we talked to whose partners refused screening were not informed they could have had a diagnostic test or did not look into it very actively. One woman explained how it didn't seem very important to her at the time because she had so many other problems, and she couldn't remember discussing it. The NHS Screening Programme is working to ensure that in future everyone receives clear and consistent information and advice about diagnostic testing, and that professionals know they should offer this to women even if their partner has not been screened.

Even though people know there is a risk that their baby may have the condition, it can still be a shock to get the results. Several people said how important their counsellor had been in providing information about the condition, advising them how to care for the baby and reassuring them that they could manage.

We spoke to two women who knew before birth that they were carriers, but did not know there was a risk their baby could have the condition. One woman's partner had been screened previously for sickle cell and was found not to be a carrier, but they did not realise he had not been screened for other possible haemoglobin variants. It was only when the newborn test showed the baby had SC disorder that they discovered the father was a carrier of haemoglobin C.

Another woman had asked for carrier screening for herself in her first pregnancy but her partner was not screened because they did not realise white people can be carriers. She also asked for newborn screening when her daughter was born. She was quite surprised to learn her daughter was also a carrier, and had an idea that the risk would reduce in successive generations. (In fact if one parent is a carrier there will always be a 1 in 2 risk that the baby will also be a carrier).

 

Last reviewed September 2015.
Last updated
September 2015.

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