Beta thalassaemia and pregnancy

Thalassaemias are conditions that affect the red blood cells and the haemoglobin they contain. Haemoglobin is the protein that carries oxygen around the body. It is produced in the bone marrow (a spongy material found inside bones) using iron that we get from our diet.

Haemoglobin is made of two matching pairs of proteins (chains). To work properly, it needs two alpha chains and two beta chains. For someone with beta thalassaemia, one or more of the beta protein chains are not made properly and the bone marrow cannot produce enough haemoglobin. This leads to anaemia and the blood cells being less able to carry oxygen.

You cannot catch beta thalassaemia. It is caused by a change in the gene that makes haemoglobin. It is an inherited condition, which means that it is passed down through families:

• If someone has two of these genes (one from each parent), they will either have the serious condition beta thalassaemia major or, if symptoms are less severe, beta thalassaemia intermedia.
• If someone has only one of these genes (from one parent), they will be a carrier of the condition.

It is one of the most commonly inherited conditions in the world. It mostly affects people whose family origins are in the Mediterranean, India, Pakistan and Bangladesh.

About 1000 people in the UK have beta thalassaemia major or intermedia.

• Beta thalassaemia major: People with beta thalassaemia major will need regular blood transfusions all their life. It can lead to too much iron in their body (iron overload), which can cause problems with organs such as the liver, heart, lungs, pancreas and pituitary gland. To prevent this happening, medication is needed to reduce the iron in their body. This is called iron chelation and is usually given by injection.
• Beta thalassaemia intermedia: The effects of beta thalassaemia intermedia can vary. Some people know they have it from childhood. Others only find out later in life when they are diagnosed with anaemia.

If you have beta thalassaemia major or intermedia, it is important to let your medical team know that you are planning to have a baby. They will be able to help you to be in the best possible health before you become pregnant.

If your iron load is high, your medical team may recommend that you have iron chelation before you get pregnant. This is because iron chelation is best avoided in the early stages of pregnancy as it might affect your baby’s development.

Sometimes having beta thalassaemia means that you might find it harder to get pregnant. You can be referred to a fertility specialist to discuss your options. If your periods are not regular, bringing down your iron levels may help.

• You should see a heart specialist who will arrange tests to check that your heart is working normally. Pregnancy places an extra strain on the heart so it is important that the medical team knows as much as possible about your heart before you get pregnant.
• You should also have your liver checked by a scan and a blood test to make sure that there is no evidence of iron overload and to check for hepatitis B and C.
• If you have diabetes, you should be referred to a diabetes specialist. It is essential that you control your blood sugar before pregnancy. If you have not previously been diagnosed with diabetes, you should be tested for this before getting pregnant.
• An underactive thyroid gland is common with thalassaemia. You should have a blood test to check that it is working properly.
• You should be offered a bone density scan if you are planning to have a baby because osteoporosis is common with thalassaemia.
• You should have your blood checked for blood group antibodies that could affect you or your baby. This is a routine test offered to all pregnant women, but the risk of having these antibodies is greater if you have had blood transfusions in the past.

You should start taking folic acid at least three months before getting pregnant. You will need 5 mg daily. This is a higher dose than the usual dose recommended for all women planning a pregnancy.

Like all pregnant women, you should also take vitamin D. Talk to your medical team about the right dose for you.

Your vaccination for hepatitis B should be up to date.

If you have had your spleen removed, you will be advised to take penicillin (or an alternative if you are allergic to penicillin) to prevent infection. You may also be advised to have additional vaccinations.

Yes. Your baby will inherit one gene from you and one from the baby’s father. If you have beta thalassaemia major or intermedia, you will pass the affected gene on to your baby.

Whether your baby has beta thalassaemia major depends on whether the baby’s father also has thalassaemia. Therefore, it is very important that you consider finding out whether your partner is also affected before getting pregnant.

• If your partner does not carry any type of thalassaemia, your baby will be a healthy carrier of beta thalassaemia.
• If your partner has beta thalassaemia major or intermedia, or is a carrier, there is a chance that your baby will have beta thalassaemia major. Specialist counselling is available. This will help you both decide whether to have tests when you become pregnant to find out if your baby has the condition. This can be a difficult decision for many couples and further information is available from the NHS Sickle Cell and Thalassaemia Screening Programme. 

You will receive antenatal care from a specialist team of obstetricians, midwives, haematologists (blood specialists), cardiologists (heart specialists) and nurse specialists.

• If you are already having regular blood transfusions, you are likely to continue to need these during pregnancy. If you are not having blood transfusions, your blood count will be monitored: you might need a transfusion if you become anaemic, if you develop symptoms and/or if your baby’s growth is affected. If your medical team is concerned about iron overload, you may be advised to have iron chelation after 20 weeks of pregnancy to reduce your iron levels.
• Your heart and liver will be checked regularly.
• You are at increased risk of developing diabetes during pregnancy. This is known as gestational diabetes. You should be tested for this at between 24 and 28 weeks. If the test confirms the diagnosis, you will be referred to a specialist team. You can find out more about this from the RCOG patient information Gestational diabetes.
• Pregnant women have a higher risk of developing blood clots in their legs (deep vein thrombosis or DVT) compared with women who are not pregnant. Thalassaemia makes you more likely to develop a venous thrombosis. You can find out more about this from the RCOG patient information Reducing the risk of venous thrombosis in pregnancy and after birth.
• If you have had your spleen removed, you may already be taking a low dose (75 mg) of aspirin. You must continue this. If you aren’t already on low-dose aspirin, you may be advised to start this during your pregnancy.
• Having thalassaemia can affect the way your baby grows in the womb by causing the placenta not to work as well as it should. This is known as fetal growth restriction. You can find out more about this from the RCOG patient information Having a small baby. Your baby’s growth will be monitored closely with regular ultrasound scans. If there are concerns about your baby’s growth, you may be advised to have your baby earlier than your due date.

Unless there are other medical reasons, you should be able to have a normal vaginal birth. You should be looked after in a consultant-led unit with neonatal facilities.

It is unlikely that you will need a blood transfusion around the time of birth but your medical team will have blood available for you.

If you have had blood transfusions during pregnancy, you may be advised to have iron chelation around the time of labour.

You will be recommended to have heparin injections for up to six weeks after your baby is born to reduce the risk of a DVT.

Yes. It is a good idea to do so. Usually you will be recommended to restart chelation treatment soon after the birth. Make sure your team knows that you are breastfeeding to ensure you receive iron chelation that is safe for your baby.