Asthma and pregnancy

Asthma is a condition that affects the small tubes (airways) that carry air to and from your lungs. If you have asthma, these tubes are more sensitive and can easily become swollen and irritated. This causes them to narrow, and there may be increased production of mucus and phlegm. This can make it harder for you to get air into and out of your lungs, causing wheezing, coughing and/or a tight feeling in your chest. Asthma can range from being mild to severe.

How pregnancy affects asthma

Pregnancy is not likely to bring on asthma if you didn't previously have it, but the effect of pregnancy on women who do have asthma is unpredictable. Around one third of pregnant women will see an improvement, one third will see no change and one third will experience a worsening of their symptoms.

A review of studies on asthma and pregnancy found that if asthma symptoms do get worse, it's most likely to happen in the second and third trimesters (after about 13 weeks), with the peak in the sixth month. Another study found that symptoms were at their worst between 24 and 36 weeks – after this, symptoms decreased and around 90% of women had no asthma symptoms during labour or birth.

The best way to ensure a healthy pregnancy is to keep your asthma well controlled by sticking to your asthma treatment plan. If your asthma is well controlled, there is little or no risk of bad outcomes for you or your baby.

As soon as you find out you're pregnant, see your GP for advice on how to manage your asthma.

Asthma treatments and pregnancy

You should continue to take prescribed asthma treatments throughout your pregnancy. Unless your asthma gets worse, your treatment can remain exactly the same as before. If you stop treatment and your asthma becomes uncontrolled, it poses a risk for your own health and will also increase the risk of your baby having a low birthweight.

Throughout your pregnancy, you can expect support from your midwife, but your usual doctor, nurse specialist or clinic will continue to manage your asthma care. If your asthma gets worse, you will be referred appropriately.

You can continue any asthma treatment while you're breastfeeding. Even when you're busy with your new baby, it's important not to neglect your own health and to keep your asthma under control.

Warning signs to watch for

Signs that your asthma may be getting worse include:

• a cough that is worse at night or in the early morning, or when you exercise
• wheezing
• breathlessness
• tightness in your chest

You are also more likely to suffer from acid reflux while you're pregnant. This condition occurs when stomach acid leaks back up into your oesophagus (gullet), and tends to make asthma worse.

If you have these symptoms, speak to your doctor or asthma specialist, who will advise you on the best treatment.

Managing your asthma during pregnancy

If you have asthma, you should have a self-management plan, which means that you can adjust your treatment to meet your needs. For example, if you have a cough or cold, your asthma may get worse, in which case you can increase your preventer inhaler (steroids), or start them if you don't take them regularly. This is completely safe during pregnancy.

While you can continue to exercise and work normally, there are some steps you can take to try to prevent your asthma from getting worse during your pregnancy:

• avoid smoking (get tips on stopping smoking in pregnancy)
• avoid allergic triggers such as pet fur
• control hay fever with antihistamines – talk to your doctor or pharmacist about which antihistamines are safe to take in pregnancy
• avoid hay fever triggers, such as mowing the lawn

Find out about having a healthy pregnancy diet, exercise in pregnancy and medicines in pregnancy.