Tommy's PregnancyHub

Health conditions and planning a pregnancy

Information on planning a pregnancy with Hepatitus B, HIV, chronic hypertension, congenital heart disease, asthma, cancer, crohn’s disease, fibroids and thyroid problems.

Many women with long-term health conditions have healthy pregnancies and babies, but there can be some risks. Talking to your doctor before you get pregnant can help make sure you and your baby stay well. For more information about the suitability of different medications in pregnancy click here.

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Congenital heart disease

Many women with congenital heart disease have a successful pregnancy, but it can put your heart under strain.

The best way to help you have a healthy pregnancy is to talk to your heart specialist (cardiologist) before you start trying to get pregnant. Ask your GP to refer you if you haven’t seen a specialist for a long time.

Your doctor will talk to you about:

  • any medications you are taking and if you need to change what you take
  • how your condition may affect pregnancy and vice versa
  • how you will be cared for during pregnancy.

They may also examine you and do some tests. Your doctor will then be able to tell you when your condition is most stable for you to start trying for a baby.

Do not stop taking your medication until you’ve talked to your doctor.

Your pregnancy

When you become pregnant you’ll be referred to a hospital maternity unit. You may be able to attend a special cardiac pregnancy clinic if there is one in your area. Ask your GP for details.

You should be cared for by a heart specialist, obstetrician (a doctor who specialises in pregnancy and childbirth) and a midwife. The treatment you have will depend on your condition. You are recommended to give birth in hospital supported by a maternity team.

Your baby

Your condition may affect your baby. For example, they may be born prematurely (before the 37th week of pregnancy). They also have a slightly higher risk of congenital heart disease if:

  • there is a family history of congenital heart disease
  • you develop gestational diabetes during pregnancy
  • you have taken certain medications during pregnancy (anticoagulants and antiepileptics).

Many problems with the baby’s development can be found during pregnancy and you should be offered regular scans. You can talk to your specialist if you have any concerns about passing on your condition to any children you have.

It is difficult to know exactly how your condition may affect your pregnancy and baby because everyone is different. You can help lessen any risks by:

  • seeing your heart specialist before you start trying for baby
  • understanding as much as you can about your condition and pregnancy
  • following all the specialist advice you’re given about managing your condition during pregnancy
  • attending all your antenatal appointments
  • not making any changes to your medication routine without speaking to your specialist.


Asthma doesn’t affect your chances of getting pregnant and most women with the condition will have a normal pregnancy.

It is important that your condition is managed well. If you are planning to get pregnant you should talk to your doctor or asthma nurse because:

  • your symptoms may get worse during pregnancy (although some women’s symptoms do not change and some improve)
  • your treatment will need to be reviewed regularly
  • poorly controlled asthma in pregnancy increases the risk of complications such as pre-eclampsia and premature birth
  • extra precautions may need to be taken during labour.

Managing your asthma during pregnancy

There are things you can do to help manage your condition during pregnancy that you can start doing while trying to get pregnant:

  • using a preventative inhaler when you get a cough or cold or as advised by your healthcare professional – speak to your asthma nurse or specialist about using preventer inhalers in pregnancy
  • avoiding smoking
  • avoiding things that trigger allergic reactions for you – for example, pet fur
  • controlling hay fever with antihistamines – talk to a doctor or pharmacist about which antihistamines are safe to take in pregnancy
  • avoiding hay fever triggers, such as mowing the lawn
  • continuing to exercise and eat a healthy diet.

Most asthma medications are safe to use in pregnancy. If your condition is well controlled there’s little risk for you or your baby. Make sure you tell your midwife, asthma nurse or specialist if you feel your symptoms are getting worse.

Do not stop taking your medication without talking to your antenatal team. This can cause problems with your health and increases the risk of your baby being born with a low birthweight.

Your baby

If you have asthma there is a small risk that your baby may also have the condition. This is more likely if you smoke during pregnancy or if your baby is born prematurely. Find out more about the benefits of stopping smoking before getting pregnant. 



Chemotherapy is a common cancer treatment where medication is used to kill cancer cells.

You should avoid getting pregnant or fathering a child during treatment because the medicines could harm the baby. Use contraception during this time, such as a condom.

Some chemotherapy medicines can reduce fertility in men and women. This means it can be more difficult to get pregnant. This is often temporary but can be permanent in some cases. Permanent infertility means you will not be able to have children naturally.

If possible, speak to your care team before you start chemotherapy about whether your fertility may be affected by the treatment. They will be able to discuss your options with you.

For women

Women may be able to have their eggs frozen to be used later in in vitro fertilisation (IVF).

Preserving men’s fertility

Men may be able to have a sample of their sperm frozen so it can be used for artificial insemination after chemotherapy. Artificial insemination (also known as intrauterine insemination) is a fertility treatment that involves inserting sperm directly into a woman’s womb.

Getting pregnant after chemotherapy

Most doctors will advise women to wait 2 years after chemotherapy before getting pregnant. This is because if your cancer were to come back it would be most likely to do so within 2 years. 

Crohn’s disease

Crohn’s disease is a condition where parts of the digestive system become inflamed. Most women who have Crohn’s disease can have a normal pregnancy and healthy baby.

However, some treatments for Crohn’s disease can affect men and women’s ability to have a baby. Some medications can also harm an unborn baby.

The best thing to do if you have Crohn’s disease and want to start a family is speak to your GP or gastroenterologist (specialist doctor).

Don’t stop taking your medications without speaking to your doctor first.

Fertility problems for women

Women may find it harder to get pregnant during a flare up but should find it easier in between. If you have had abdominal or pelvic sepsis, surgery or adhesions, this may also make it more difficult to get pregnant.

Fertility problems for men

For most men, Crohn’s disease itself is unlikely to affect their fertility. But some medications used to treat the condition may temporarily affect their ability to father a child.

Sometimes pelvic surgery is recommended as a treatment. This can lead to erectile dysfunction or ejaculation problems, which can make getting their partner pregnant more difficult.

Getting pregnant

Speak to your GP or gastroenterologist (specialist doctor) if you have any concerns about your fertility and if you want to start a family.

For both men and women, your drug treatment may need to be changed while you’re trying for pregnancy. It’s important that your condition is being managed well and you are in remission before trying to get pregnant. This reduces the risk of your condition flaring up during pregnancy.

Because you don’t know when you will become pregnant, the best thing to do is to keep using contraception until you have seen your doctor. Don’t stop taking your medication without getting advice first.


Fibroids are non-cancerous growths that develop in or around the womb (uterus).

Most women don’t experience any symptoms of fibroids, but they can cause problems in some cases. Whether you will have problems depends on things like where your fibroids are in your body and how big they are.

Fertility issues

If a woman has large fibroids this can lead to infertility.

If you have a submucosal fibroid (a fibroid that grows from the muscle wall into the cavity of your womb), this may make it harder for you to become pregnant.

Treatments and pregnancy

If you take medication for fibroids this shouldn’t prevent you from getting pregnant. But if you use injected progestogen, it can delay pregnancy for up to 12 months after you stop using it.

Endometrial ablation is a minor procedure sometimes used to treat fibroids that involves removing the lining of the womb. It may still be possible to get pregnant after having this procedure, but it isn’t recommended for women who want to have children because it can increase the risk of miscarriage.

Problems during pregnancy

If fibroids are present during pregnancy it can sometimes lead to problems. There is a risk of:

If you have fibroids and want to get pregnant speak to your GP for more information and advice.

Thyroid problems


Having an overactive thyroid gland (hyperthyroidism) or an underactive thyroid gland can affect female fertility. This means it may be more difficult to get pregnant.

But there is no reason why you should not have a successful pregnancy and healthy baby if your condition is under control.

Speak to your GP if you have an overactive or underactive thyroid and want to get pregnant. You may be referred to an endocrinologist (a doctor who specialises in hormone control) who may do some tests to assess your thyroid function. It is important that your condition is well controlled before you conceive.

Problems during pregnancy

If an underactive thyroid is not well controlled in pregnancy it can increase the risk of gestational diabetes.

If an overactive thyroid is not well controlled in pregnancy it can increase the risk of:

Some treatments for an overactive thyroid (hyperthyroidism) can harm an unborn baby so make sure you continue to use contraception until you speak to your doctor. They may recommend you switch to a different treatment while you try to get pregnant.

Radioiodine treatment

This is a treatment for an overactive thyroid (hyperthyroidism). Radiation is used to damage your thyroid, reducing the amount of hormones it can produce. This is a highly effective treatment but is not suitable if you are pregnant.

If you have recently had radioiodine treatment you are advised not to get pregnant for at least six months afterwards.

Hepatitis B

At the booking appointment, all women are offered a blood test that includes a test for hepatitis B.

Hepatitis B is a liver infection which is caused by a virus. You can get hepatitis B from blood and other body fluids, for example through sexual contact or infected needles. It can also be passed from a mother to their baby during childbirth. 

Hepatitis B can cause flu-like symptoms in adults and doesn’t usually need treatment but it’s more likely to lead to long term infection and liver damage in children so it is very important to reduce the risk of passing it on as much as possible. By following a treatment plan it can be prevented in 90 to 95% of cases.

If you’re pregnant, you will need extra care to prevent passing the virus to your baby. Some women will need to take medication in the third trimester.

If you have hepatitis B, your baby can have a vaccine after they’re born to stop them getting the virus.

They will need to have 6 doses of the vaccine. They will have the first dose within 24 hours of birth and then at 4, 8, 12 and 16 weeks. They will have the final vaccination when they’re a year old, together with a blood test to check that they don’t have the virus.

It’s important that your baby has all 6 doses of the vaccine at the right time.

More support and information

NHS Choices has information on all conditions listed here, including common symptoms and how they are diagnosed and treated.

Bumpes is a website providing information on the effects that medicines, recreational drugs and chemicals can have on an unborn baby.

British Heart Foundation has more information about heart problems, fertility and pregnancy

British Thyroid Foundation has more information about thyroid problems, fertility and pregnancy

Cancer Research UK has more information about cancer and how it can be treated, your fertility and pregnancy.

Crohn’s and Colitis UK has more information about Crohn’s, fertility and pregnancy  


1. NHS Choices (accessed 01/06/2018) Congenital heart disease, Page last reviewed: 12/06/2018 Next review due: 12/06/2021,

2. British Heart Foundation Congenital heart disease (accessed 01/06/2018)

3. NHS Choices (accessed 01/06/2018) Asthma Page last reviewed: 19/02/2018 Next review due: 19/02/2021,

4. NHS Choices (accessed 01/06/2018 Asthma and pregnancy Page last reviewed: 15/03/2018 Next review due: 15/03/2021 

5. NHS Choices (accessed 01/06/2018) Chemotherapy Page last reviewed: 22/02/2017 Next review due: 22/02/2020, 

6. Cancer Research UK (accessed 01/06/2018) Ways to keep your fertility Page last reviewed: 27/02/2018

7. NHS Choices (accessed 01/06/2018) Crohn’s disease Page last reviewed: 04/04/2018 Next review due: 04/04/2021,

8. Clinical Knowledge Summaries (Aug 2017) Pre-conception advice and management 

9. NHS Choices Fibroids (accessed 01/062018)Fibroids Page last reviewed: 17/08/2015 Next review due: 02/08/2018,

10. NHS Choices (accessed 01/06/2017) Infertility Page last reviewed: 14/02/2017 Next review due: 14/02/2020

11. Y, Shuai et al Low thyroid hormone in early pregnancy is associated with an increased risk of gestational diabetes mellitus The Journal of Clinical Endocrinology & Metabolism, Volume 101, Issue 11, 1 November 2016, Pages 4237–4243

12. NHS Choices (accessed 01/06/2018) Overactive thyroid (hyperthyroidism) Page last reviewed: 22/09/2016 Next review due: 22/09/2019

NHS (2018) Screening for hepatitis B, HIV and syphilis.

Public Health England (2019) Hepatitis B: the green book, chapter 18.

NHS (2019) Hepatitis B: overview.

National Institute for Health and Care Excellence (2014) Hepatitis B. Quality standard [QS65]

Public Health England (2019) Hepatitis B: the green book, chapter 18.

NHS (2018) Screening for hepatitis B, HIV and syphilis.

Review dates
Reviewed: 12 June 2018
Next review: 12 June 2021

This content is currently being reviewed by our team. Updated information will be coming soon.