If you're a carrier of sickle cell, it means you carry one of the genes that causes sickle cell disease, but you do not have the condition yourself.
It's also known as having the sickle cell trait.
People who carry sickle cell will not develop sickle cell disease, but may be at risk of having a child with sickle cell disease and may occasionally need to take precautions to stop them becoming unwell.
You can find out if you're a carrier of sickle cell by having a simple blood test.
The NHS Sickle Cell and Thalassaemia Screening Programme has a detailed leaflet about being a sickle cell carrier (PDF, 773kb).
Anyone can be a carrier of sickle cell, but it's much more common in people from certain ethnic backgrounds.
In the UK, most people who carry the sickle cell trait have an African or Caribbean family background.
Screening for sickle cell disease is offered to all pregnant women in England, although most women will be at low risk and will not need to have a blood test to check if they're a carrier.
Anyone can ask to have a free blood test to find out if they're a carrier at any point.
This can be useful if:
You can request the test from your GP surgery or nearest genetic counsellor, who'll discuss the result and implications with you if you're found to carry sickle cell.
If you carry the sickle cell trait, you're at risk of having children with sickle cell disease, although this can only happen if your partner is also a carrier or has sickle cell disease themselves.
If you're planning to have a child and you know you're a carrier, it's a good idea for your partner to be tested.
If you and your partner both carry sickle cell, there's a:
If both of you are carriers and you're planning to have a baby, talk to your GP about getting a referral to a genetic counsellor, who can explain the risks to your children and what your options are.
PGD is similar to IVF, but the resulting embryos are tested to check that they do not have sickle cell disease before they're implanted in the womb.
The Human Fertilisation and Embryology Authority (HFEA) has more information about PGD.
You're not at risk of developing sickle cell disease if you carry the sickle cell trait.
The only time you may be at risk of health problems is in rare cases where you might not get enough oxygen, such as:
There's also a very small risk of developing kidney problems associated with carrying sickle cell.
Apart from these uncommon situations, you can lead a completely normal and healthy life if you're a sickle cell carrier.
People who are carriers of the sickle cell trait are also at risk of having a child with a blood disorder if their partner is a carrier of a different type of blood disorder.
You can find more detailed information about some of the other types of carrier in these leaflets: