Screening Programmes for Sickle Cell and Thalassaemia

Sickle cell disease (SCD) and thalassaemia are inherited blood disorders. If you're a carrier of the sickle cell or thalassaemia gene, you can pass these health conditions on to your baby. All pregnant women in England are offered a blood test to find out if they carry a gene for thalassaemia. Those at high risk of being a sickle cell carrier are offered a test for sickle cell. If the mother is found to be a carrier, screening is also offered to the father. This test should be offered before you're 10 weeks pregnant. It's important the test is done early. If you find out you're a carrier, you and your partner will have the option of further tests to know if your baby will be affected.

About sickle cell and thalassaemia

Sickle cell disease and thalassaemia affect haemoglobin, a part of the blood that carries oxygen around the body.

People who have these health conditions need specialist care throughout their lives.

Sickle cell disease

People with sickle cell:

• can have episodes of very severe pain
• can get serious life-threatening infections
• are usually anaemic (their bodies have difficulty carrying oxygen)

 

Babies with sickle cell disease can receive early treatment, including vaccinations and antibiotics.

This, along with support from their parents, will help prevent serious illness and allow the child to live a healthier life.

Thalassaemia

People with thalassaemia can be affected by anaemia and some may need frequent blood transfusions, as well as injections and medicines throughout their lives.

There are also other less common, and less serious, haemoglobin disorders that may be found through screening.

Why could I be offered screening for sickle cell and thalassaemia early in pregnancy?

Screening is offered to find out if you're a carrier of a gene for sickle cell or thalassaemia and therefore likely to pass it on to your baby.

Genes are the codes in our bodies for things like eye colour and blood group.

Genes work in pairs: for everything we inherit, we get 1 gene from our mother and 1 gene from our father.

People only have sickle cell disease or thalassaemia if they inherit 2 unusual haemoglobin genes: 1 from their mother and 1 from their father.

People who inherit just 1 unusual gene are known as carriers or as having a trait.

Carriers are healthy and do not have the disease.

Sickle cell carriers can experience some problems in situations where their bodies might not get enough oxygen, such as having a general anaesthetic.

All carriers can pass the unusual gene on to their children.

When both parents are carriers

When both parents are carriers, each time they're expecting a child there's:

• 1 in 4 chance of the child not having or carrying the disease
• 2 in 4 chance of the child being a carrier
• 1 in 4 chance of the child having the disease

Anyone can be a carrier of haemoglobin disease. But it's more common among people with ancestors from Africa, the Caribbean, the Mediterranean, India, Pakistan, south and southeast Asia, and the Middle East.

What does the screening test involve?

Screening for sickle cell and thalassaemia involves a blood test. It's best to have the test before you're 10 weeks pregnant.

This is because you'll have the option of more tests to find out whether your baby will be affected if this first test shows you're a carrier of a blood disorder.

By having the test early, you and your partner can find out about all your options and make an informed decision if your baby is at risk of inheriting a blood disorder.

All pregnant women are offered a test for thalassaemia, but not all women are automatically offered a test for sickle cell.

In areas where haemoglobin diseases are more common, all women will automatically be offered a blood test for sickle cell.

In areas where haemoglobin diseases are less common, a questionnaire is used to identify your family origins and the origins of the baby's father.

If the questionnaire shows that either you or the baby's father is at risk of being a sickle cell carrier, you'll be offered a screening test.

You can ask to have the test even if your family origins do not suggest the baby would be at high risk of a haemoglobin disease.

Can this screening harm me or my baby?

No, the screening test cannot harm you or your baby, but it's important to think carefully about whether or not to have this test.

It can provide information that may mean you have to make further important decisions.

For example, you may be offered further tests that have a risk of miscarriage.

 

Do I have to have this screening test?

No, you do not have to have the screening test.

Some people want to find out if their baby could have sickle cell disease or thalassaemia, while others do not.

Getting your screening results

The test will tell you if you're a carrier or not, or whether you have the disease yourself.

You'll get the result of the blood test within a week. The person doing the test will discuss the arrangements for getting your results with you.

If you're found to be a carrier of sickle cell or thalassaemia, you'll be contacted by a specialist nurse or midwife counsellor for genetic counselling.

 

Further tests if the mother is a carrier

Tests to see if the father is a carrier

If the screening test finds that you're a carrier of a haemoglobin disease, your baby's father will also be offered a blood test.

If tests show the father is not a carrier, your baby will not have sickle cell disease or thalassaemia and you will not be offered further tests in pregnancy.

But there's still a 1 in 2 chance your baby could be a carrier and pass on the unusual gene to their children.

You can discuss the implications of you or your baby being a carrier with your GP or a healthcare professional at your local sickle cell and thalassaemia centre.

 

Tests when both parents are carriers

If tests show your baby's father is also a carrier, there's a 1 in 4 chance that your baby can have the disease.

You'll be offered further tests called diagnostic tests to find out if your baby is affected.

A diagnostic test will tell you:

• if your baby has sickle cell disease, thalassaemia or another haemoglobin disorder
• if your baby is a carrier
• if your baby is completely unaffected

If the baby's father is not available and you have been identified as a carrier, you'll be offered a diagnostic test.

About 1 in 200 diagnostic tests result in a miscarriage. It's up to you whether or not to have the diagnostic test.

It can be a very difficult time if you're told you're at risk of having a baby with sickle cell disease or thalassaemia major. Talk to your midwife, specialist nurse or doctor about your options.

You can also get information and support from the charity Antenatal Results and Choices (ARC).

For more information click here

Screening Programmes

Your antenatal blood test results: you are a delta beta thalassaemia carrier - click here

Your blood test result: you are a haemoglobin O Arab carrier - click here

Your antenatal blood test results: you are a haemoglobin C carrier - click here

Your antenatal blood test result: you are a haemoglobin D carrier - click here

Your blood test result: you are a haemoglobin E carrier - click here

Your antenatal blood test result: you are a haemoglobin Lepore carrier - click here

Information for fathers invited for a screening test for sickle cell disease and thalassaemia major - click here

Sickle cell and thalassaemia screening: your baby carries a gene for sickle cell - click here

Baby carries a gene for unusual haemoglobin: description in brief - click here

Information and choices for women and couples at risk of having a baby with sickle cell disease - click here

Information and choices for women and couples at risk of having a baby with thalassaemia major - click here

Information for fathers invited for a screening test for sickle cell disease and thalassaemia major - click here

Screening in pregnancy: CVS and amniocentesis information for parents - click here

Screening tests for you and your baby (STFYAYB) - click here