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.