Thalassaemia and pregnancy : University College London Hospitals NHS Foundation Trust

This web page provides information about pre-pregnancy planning if you have thalassaemia. It also explains how to manage your condition when pregnant and after delivery.

If you have thalassaemia trait (carrier), visit the UK government website where you can find the following information:

Beta thalassaemia carrier: description in brief and
Delta beta thalassaemia carrier: description in brief.

Thalassaemia is disorder of the body’s red blood cells that is genetically inherited and lifelong. It is caused by an abnormality in the genes that control haemoglobin, the part of red blood cells that carries oxygen around the body. This results in the reduced amount of haemoglobin.

People who need regular transfusions have transfusion-dependent thalassaemia (TDT). TDT was previously known as thalassaemia major. Some people may not need transfusions until much later in life, or perhaps never. These people have non-transfusion-dependent thalassaemia (NTDT), previously known as thalassaemia intermedia. For more information, visit our web page Thalassaemia (transfusion- dependent and non-transfusion-dependent).

If you have thalassaemia, you should find out whether your partner is also affected. You should do this before getting pregnant or fathering a child.

Your baby will not have thalassaemia or sickle cell disorder if your partner:

does not have a haemoglobin disorder, and
is not a carrier of thalassaemia or an abnormal haemoglobin gene.

But your baby will be a carrier of one of your two abnormal haemoglobin genes.

You or your haematology team can arrange an appointment at the haemoglobinopathy genetics clinic if:

your partner has a haemoglobin disorder
your partner is a carrier of an abnormal haemoglobin gene, or
you are unsure what their haemoglobin type is.

During this appointment, any necessary tests will be carried out. Both you and your partner may also receive specialist counselling if needed. The information and counselling will help you both decide whether to have tests during pregnancy to find out if your baby has the condition. Or you may choose pre-implantation genetic diagnosis. This involves screening the genes of embryos created through IVF for any conditions that can be passed on by the parents.

We realise that this can be a difficult decision for many couples. Further information about screening for thalassaemia is available on the NHS website: nhs.uk/conditions/thalassaemia/diagnosis

Let your thalassaemia team know that you are planning to have a baby. They will:

help you to be in the best possible health before you become pregnant
advise you which contraception is best for you until then
discuss how thalassaemia can be passed on to your child, using both your and your partner’s blood test results
explain how this might affect your baby.

Because of this, it’s important that your partner is tested for haemoglobin disorders before you stop using contraception.

To find out more about sexual health, contraception and preparing for pregnancy, visit our web page.

Your thalassaemia team will also talk to you about any complications you may have during pregnancy. They will recommend some tests and checks, including:

a detailed scan of your heart (echocardiogram)
blood pressure, urine and blood tests
a special eye test (retinal screening) to detect problems at the back of the eyes
MRI scans to measure iron
bone density scans
diabetes tests (oral glucose tolerance test).

It’s important that your health is in the best possible condition before you get pregnant to keep you and your baby healthy during pregnancy and delivery. This is especially important for managing your iron levels.

All heart and blood pressure medicines should be reviewed before pregnancy. This is to make sure that they are safe to take while you’re expecting.

You should also start taking folic acid at least three months before trying to get pregnant.

Women who are on regular transfusions and iron chelation

It may take several years for some women to become physically ready for healthy pregnancy. Certain treatments often need to be modified to make sure that you and the baby stay well. These include iron chelation, hormone therapy and diabetes management.

If you are receiving treatment to help you conceive, you should stop desferrioxamine on the day you take pregnyl. If you conceive naturally, you need to stop desferrioxamine as soon as you miss your period and have a positive pregnancy test. The iron levels have to be well controlled to avoid serious complications during pregnancy.

Poor control of diabetes and other hormone treatments, like thyroid replacement, can have a negative impact on you and the baby. It can also affect the success of fertility treatments.

Certain medicines, such as bisphosphonates, are not safe in pregnancy. They need to be stopped several months before you try to conceive.

To make sure that you and your baby are well, we recommend the following targets:

low liver iron levels (generally less than 5 mg/g/dw).
minimal or no cardiac iron loading (T2* above 20ms). If it is below 20ms, you will need a cardiac review before conception.
fructosamine levels lower than 330 nmol/l.
normal TSH and free T4 levels.

Women who have non-transfusion-dependent thalassaemia

Most women with this type of thalassaemia are naturally fertile and often take no treatment for their condition. But it’s important to review all medicines before planning a pregnancy and stop any that may be harmful to the baby. For example, hydroxyurea should be stopped three months before trying to conceive. If anaemia develops and gets worse, you may need to start blood transfusions.

Your thalassaemia team will also check your blood for antibodies that may have developed after previous blood transfusions or pregnancies. And they will make sure all your vaccinations are up to date.

For more information about medications, vaccinations and travel in thalassaemia, visit our web page.

If you’re finding it difficult to get pregnant, it may be because you had a lot of excess iron as a child. Or it may be for reasons unrelated to iron overload. If you have any questions or concerns about your fertility, please talk to your thalassaemia specialist.

Most women with thalassaemia have straightforward pregnancies without any serious problems.

But pregnancy is physically demanding and you may need more frequent blood transfusions. To make sure that you and your baby thrive during pregnancy, you will also see many healthcare professionals and have frequent scans. This will help to identify any potential problems early and manage them properly.

Pregnant women are generally at an increased risk of developing blood clots in the legs and lungs. Thalassaemia raises this risk further. To find out more about reducing your risk of blood clots when pregnant and after birth, visit the Royal College of Obstetricians and Gynaecologists website.

Women with transfusion-dependent thalassaemia

If you have diabetes, hypothyroidism or cardiac iron loading you will need specialist support and monitoring during your pregnancy.

If your iron levels were not well controlled at the start of your pregnancy, your thalassaemia specialist and cardiology team might restart chelation therapy with desferrioxamine during your second trimester. For example, if you had significant cardiac iron loading (T2* less than 10ms) or severe liver iron overload. They may also suggest an MRI of your heart during the pregnancy.

When you come to the hospital for delivery, you will receive an infusion of desferrioxamine into a vein. Women with thalassaemia have a slightly higher chance of needing a caesarean delivery. But you should be able to have a natural delivery unless there are health concerns for you or your baby.

Women who have non-transfusion-dependent thalassaemia

If your hemoglobin drops to levels much lower than those before you were pregnant, you may need regular blood transfusions throughout your pregnancy.

Sometimes, even if the anaemia isn’t causing problems for you, it might affect your baby’s growth. If this is the case, you will need to start regular transfusions to make sure that your baby gets enough oxygen and nutrients.

Transfusions during pregnancy are safe for both you and your baby. But if you start receiving transfusions later in life, there is a higher risk of developing antibodies. This could make future transfusions more challenging. If iron overload develops, it can be managed after delivery.

The obstetricians, haematologists, endocrinologists or cardiologists may also recommend other treatments during your pregnancy. For example, you may need:

low molecular weight heparin (LMWH) if you have had a splenectomy
LMWH and aspirin if your baby is not growing well
insulin if you develop diabetes.

Your healthcare team will talk to you about these treatments in detail and answer any questions you may have. If you have any other concerns, contact your maternity unit and haematology team.

It’s important that you tell your haematology team and your GP as soon as you find out you are pregnant. You will have consultant-led care rather than midwifery-led care because of your thalassaemia. But you will often see a midwife too.

You will see specialist haematology and high-risk obstetric teams throughout your pregnancy. If you didn’t have the recommended tests in the previous year, you should have them when you’re pregnant.

Many vaccinations are safe in pregnancy and should also be updated if necessary. Please speak to your team about this.

You should have your appointments at the antenatal clinic at least every four weeks until your 24th week. And then every one to two weeks until you have had your baby. At each visit you will have your blood pressure checked and your urine tested. As well as the routine scans, you should have extra scans to check that your baby is growing normally.

Tiredness and breathlessness can be signs of anaemia. If you notice these symptoms, let your healthcare team know. You may need more frequent blood transfusions or larger amounts of blood than usual. This may apply even if your haemoglobin levels are higher than they typically are.

Your team in the high-risk obstetric clinic will assess your risk of blood clots early in your pregnancy. If there are any other risk factors that make you more likely to get a blood clot, for example if you are overweight, you may need to have daily LMWH injections throughout your pregnancy.

Your doctor may advise you to take a low dose of aspirin if:

you have had your spleen removed
the level of your platelets is less than 600, or
you have previously had a blood clot.

Both LMWH injections and aspirin are safe to take while you are pregnant and should be continued for six weeks after your baby is born.

You should continue your folic acid (5 mg) once a day and, if your spleen has been removed, penicillin V 250mg twice a day. You should also continue to take all your vitamin D and calcium supplements.

If you take thyroxine or insulin, you will need frequent monitoring. Your dose may also need to be adjusted to maintain good control of your condition.

Some oral medicines for diabetes are not safe to take in pregnancy. If you take an oral medicine for your diabetes, speak to your diabetes doctor as soon as possible. You may need to start insulin instead.

If you are at an increased risk of blood clots, you may need to take a blood-thinning medicine. This is usually a low molecular weight heparin (LMWH), such as enoxaparin or tinzaparin. If you don’t have to take it when you are pregnant, it is likely that we will give it to you after delivery.

Your doctor will talk to you in detail about your medicines.

If you became pregnant unexpectedly and had not stopped your hydroxyurea, you should stop it as soon as you have a positive pregnancy test.

Chelation (treatment to reduce iron overload) is also stopped in pregnancy. You may need to start desferrioxamine during the second trimester if the iron levels are not safe. Deferiprone and deferasirox should not be used during pregnancy.

Like all pregnant women, you should not take ibuprofen before 12 weeks and after 28 weeks of pregnancy without talking to your doctor. This is because it could cause problems for your baby. You can take paracetamol and codeine instead as pain relief.

If you become unwell, contact the haematology advice line or the haematology team. During your first antenatal appointment, your midwife will also give you contact numbers for any pregnancy-related questions or issues.

We will check what is causing your symptoms and prescribe you antibiotics if necessary. We may also give you LMWH injections to reduce the risk of blood clots. We will monitor you closely, often in a high-dependency area of the hospital. We will check your baby’s wellbeing too.

You should have your baby in a hospital that is able to manage potential thalassaemia-related complications.

If you are on regular transfusions, we will give you a low dose of desferrioxamine infusion soon after you arrive in the hospital. You will have the infusion by a drip over 24 hours. This will help to control the free iron in your blood during labour and reduce stress on your heart. Desferrioxamine infusions will not cause any problems for your baby. We will monitor their heartbeat closely throughout labour.

You should be able to have a vaginal birth if there are no complications and you are in good health.

You should see an anaesthetist before you go into labour to discuss pain relief. This is often possible in the high-risk obstetric clinic.

All the usual methods of pain relief should be suitable for you.

We will encourage you to get up and walk about to prevent blood clots from forming in your legs. You may need to wear special stockings and have daily LMWH injections for at least a week to reduce this risk further. Depending on any other risk factors relevant to you, and after caesarean section, you may need to continue LMWH injections for six weeks.

Chelation will start soon after delivery. If you are going to breastfeed, it will need to be desferrioxamine (Desferal®).

You will be offered the support you need to breastfeed.

Parents in the UK can have their babies tested for thalassaemia and other conditions. This involves taking a blood sample from the baby’s heel around day five after birth. The test is usually done by the community midwife when you are at home, or in hospital if you or your baby are still there.

The results usually take four weeks to come back. If there is a risk that your baby could have sickle cell disorder or transfusion-dependent thalassaemia, we can arrange for the blood test to be done in hospital. This way you can have the results on the same day or day after.

If your baby has a blood test to check if they are a carrier, the sample usually needs to be processed by the genetics laboratory. This can take a few days longer.

The contraceptive methods listed below are safe and effective after pregnancy:

progesterone-only pills
contraceptive injections (Depo-Provera®)
hormone-releasing implants (Nexplanon®)
the Mirena® coil
barrier methods (such as condoms, sheaths and caps).

You may also be able to use the combined oestrogen and progesterone pill (‘the pill’) or copper coil. But the pill might not be the safest option for some people due to increased risk of blood clots.

To find out more about contraception, please talk to your GP or a family planning specialist. You can also visit our web page Sexual health, contraception and preparing for pregnancy: Information for people with thalassaemia and sickle cell disorder (SCD).

Thalassaemia is one of the most common inherited single-gene disorders in the world.
Most women with thalassaemia have a relatively straightforward pregnancy and a healthy baby.
Chelation is usually stopped in pregnancy. You may need more frequent blood transfusions.
If you are planning a pregnancy, let your thalassaemia team know. They will review your medicines and vaccinations, and make sure your checks are up to date.
You and your partner can meet a specialist or counsellor to discuss the risk of thalassaemia being passed to your baby. They will also tell you about the tests available to you.
A specialist team will look after you and your baby very closely during pregnancy.
We advise that you have your baby at some point before your due date.
We will offer you support to breastfeed.