Screening for sickle cell and thalassaemia disorders
You'll be offered a screening test for sickle cell and thalassaemia disorders during or shortly after your first midwife visit. These conditions are sometimes referred to as haemoglobinopathies.
You should decide as early as possible if you want to have the tests as they should be done early in your pregnancy, ideally by 10 weeks. However, it can still be helpful to have them later.
Results from your blood test and your answers to the Family Origin Questionnaire will be used to screen for these conditions.
Why will I be screened for sickle cell and thalassaemia?
Sickle cell and thalassaemia are serious, inherited blood disorders that are passed on from parents to children through altered haemoglobin genes. Haemoglobin is in red blood cells and carries oxygen around the body.
People who have these conditions will need specialist care throughout their lives. Your baby's father might also be offered a test. This will make the results more accurate.
Sickle cell disease
Sickle cell disease is a blood disorder. People with certain types of sickle cell disease:
- can experience attacks of very severe pain
- may have serious, life-threatening infections
- are usually anaemic (which means that their blood is not good at carrying oxygen)
- may need medicines and injections throughout their lives, to stop them from getting infections
Testing new babies for sickle cell
All newborn babies are offered a ‘blood spot’ screening test, ideally when they are 5 days old.
Your midwife will prick your baby’s heel and put a few spots of blood onto a card. The card is sent to a laboratory where tests are done for 9 conditions, including sickle cell.
You’ll get the results on or before your baby’s check-up at 6–8 weeks.
Learn more about sickle cell disorder
People with certain types of thalassaemia:
- may be very anaemic
- may need blood transfusions every 4 to 6 weeks
- may need injections and medicines throughout their lives
Genes determine your characteristics, from the colour of your hair to your blood group. For all our characteristics, we get one gene from each parent.
People only have these disorders if they get 2 altered haemoglobin genes – one from their mother and one from their father. People who get just one altered gene are known as 'carriers'.
The test aims to identify carriers of these disorders. Carriers don't have either sickle cell or thalassaemia. But if a carrier has a baby with someone who is also a carrier, or who has sickle cell or thalassaemia, there's a higher chance that their baby could have one of the disorders or be a carrier.
Although sickle cell carriers are healthy, they can have issues when their bodies don't get enough oxygen (when having an anaesthetic, for example). Knowing you’re a carrier can help you manage these situations. People who are thalassaemia carriers don't experience these issues.
If your screening tests show a 'higher chance' result for sickle cell disorder or thalassaemia, you'll be offered diagnostic tests to confirm if your baby has the condition.
Diagnostic tests have some risks, and won't be offered to everybody.
Who's more at risk?
People who inherit 2 altered haemoglobin genes can go on to develop sickle cell disorder or thalassaemia.
Anyone can be a carrier. But you’re more likely to carry the altered genes if your ancestors (parents, grandparents, and those further back in your family line) came from places where malaria was common, such as:
- an African country
- South Asia (India, Pakistan or neighbouring countries)
- the Caribbean
- the Middle East
- South America
- Southern Europe
- East and South-East Asia (China, Hong Kong, Malaysia or their neighbours)
People from Poland may also be affected because many generations ago some Polish people moved from areas where malaria was common.
Family Origin Questionnaire
To help find out if you or your baby’s father have a chance of carrying genes for sickle cell disorder or thalassaemia, your healthcare professional will ask you questions from the Family Origin Questionnaire.
The aim is to find out where your immediate family and your ancestors came from, and if you have a higher chance of carrying the genes.
Please tell your midwife if you and your partner are related by blood. If you each have inherited genes from a shared relative, it may be more likely that you’re both carriers.
Why might your baby's father be invited for sickle cell and thalassaemia screening?
Your baby’s father may be invited for a blood test too, as testing both parents gives more accurate results.
You may be offered a diagnostic test to confirm whether or not your baby has, or is carrying, one of the conditions if:
- both parents are found to be carriers
- both parents are found to be affected by one of the conditions
- it's not possible to test both parents
What if your baby's father is also a carrier?
If you and your baby's father both carry the gene for sickle cell, thalassaemia or another blood disorder, there's usually a:
- 25% (1 in 4) chance that your baby will not have a disorder
- 50% (2 in 4) chance that your baby will be a healthy carrier
- 25% (1 in 4) chance that your baby will have a disorder
The chances stay the same with each pregnancy.
Please give staff as much information as you can if you have an assisted pregnancy - for example if you had in vitro fertilisation (IVF). This could affect your screening result. Your healthcare professional will explain your results.
As with all screening tests, screening for sickle cell and thalassaemia is not 100% accurate. Diagnostic testing is the only way to know for sure if your baby has one of the conditions.
Your healthcare professional will help you to understand what it'll mean if the results show your baby has a blood disorder. They’ll talk with you about the care that's available and whether you wish to continue with your pregnancy.
A genetic counsellor is a professional who's specially trained to give you information and support if you've questions or concerns about a genetic condition. Your midwife or GP will be able to refer you.
Blood condition leaflets for adults
Public Health Scotland produces leaflets to support parents who've had a blood condition (sickle cell disease or thalassaemia) detected through screening.
These leaflets are available in English and other languages. They aren't available in print.
Blood screening test results information for adults
26 January 2023
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