Key learning points
- Existing asthma symptoms can improve, worsen, or stay the same during pregnancy
- When asthma is well controlled, there’s little to no risk to mother or baby
- Better asthma control could save hundreds of lives each year and improve outcomes
Asthma can emerge at any age. But studies suggest that hormonal changes at key life stages such as puberty, pregnancy and menopause may have an effect.
During pregnancy, around a third of women find their asthma gets better.
A third experience more symptoms, and
a final third don’t notice any change.
In general, pregnant women who have asthma should be treated in the same way as anyone else. But research shows that people are most susceptible to developing new habits at times of upheaval, such as moving house or preparing for parenthood.
So community midwives have a unique opportunity to investigate women’s barriers to adherence (perhaps fear of side-effects for themselves or their baby) and encourage better adherence to asthma medicines, as well as other behaviours that will benefit mother and child for years to come, such as smoking cessation or taking regular exercise.
The key things women can do to keep their asthma controlled, and have a better chance of staying well in their pregnancy, are:
- Use a personalised written asthma action plan, which describes what to do: every day; when asthma symptoms get worse; and during an asthma attack.
- Studies show that people who use an asthma action plan are four times less likely to have to go to hospital because of their asthma than those without.
- Review their symptoms and action plan regularly with a GP or nurse. British Thoracic Society guidelines recommend that adults have an asthma review at least once a year.
- Ensure the woman’s asthma is recorded on the birth plan so that everyone responsible for her care is aware of it, and of any extra concerns she may have.
- Take their medicines as prescribed. Even women who were adherent before pregnancy may be wary about taking preventer medication.
You can reassure women that asthma medicines will not harm their baby, and that using medicines to keep good control of asthma symptoms gives them the best chance of staying well too.
Medicines and pregnancy
The flu jab is recommended for pregnant women as it reduces the likelihood of complications resulting from flu to mother or baby, and protects the baby from flu for the first few months of life.
The medicines used to treat asthma are safe in pregnancy and won’t harm an unborn baby. This includes reliever inhalers (usually blue); preventer inhalers; long-acting and combined relievers; theophylline, and steroid (prednisolone) tablets.
The first action should be to continue existing treatment.
If a woman has not been prescribed inhaled treatments before pregnancy, or has not been taking them, refer her to her usual prescriber.
Leukotriene receptor antagonists (montelukast and zafirlukast) aren’t usually started during pregnancy, but if a woman has used them to control asthma well before pregnancy, a GP or asthma nurse may recommend that they are continued.
What to expect
Women who find that their asthma gets worse during pregnancy are likely to see the biggest difference during the second and third trimester, peaking around the sixth month.
Often symptoms improve again in the last four weeks – a large cohort study found that 90% of women with asthma had no symptoms during labour or delivery.
If asthma gets worse
Uncontrolled asthma is associated with many maternal and foetal complications, including hyperemesis, hypertension, pre-eclampsia, vaginal haemorrhage, complicated labour, foetal growth restriction, pre-term birth, increased perinatal mortality, and neonatal hypoxia.
But when asthma is well controlled, there’s little or no increased risk to mother or baby. Some women find that their nose feels more congested, or they experience more hay fever symptoms while pregnant.
Around four in five people with asthma also have a pollen allergy (hay fever) and many tell us that it contributes to increased asthma symptoms and attacks.
Encourage women to treat hay fever symptoms as soon as possible, or, if they know they react at certain times of year, to start treatment around two weeks before.
If asthma seems to be getting better
Encourage women not to be complacent; although asthma symptoms can vary through life, it’s always in the background, and they should continue to use preventer medicines as prescribed to reduce the underlying inflammation and reduce their sensitivity to triggers.
Your main aim is to reassure the mother that the possible side-effects of preventer medication throughout pregnancy are far outweighed by the risks of poor asthma control and a potential asthma attack.
Asthma attacks should always be treated as an emergency, whether the patient is pregnant or not.
Advise the woman to:
1 Sit up straight – don’t lie down. Try to keep calm.
2 Take one puff of the reliever inhaler (usually blue) every 30-60 seconds, up to a maximum of 10 puffs.
3 If they feel worse at any point while using the inhaler or they don’t feel better after 10 puffs or if they are worried at any time, call 999 for an ambulance.
4 If the ambulance is taking longer than 15 minutes to arrive, repeat step 2.
Make sure women are clear about how to recognise an asthma attack and that they and those around them know what to do.
They may find it helpful to take a photo of their written asthma action plan on their phone, so it’s always to hand and can easily be shared, or to nominate an ‘asthma buddy’ who knows what to do when symptoms get worse and where to find a reliever inhaler.
Asthma and genetics
It’s not possible to predict whether a baby will have asthma, although we know that some factors make it more likely:
- Premature birth or low birth weight.
- At least one parent (especially the mother) having asthma.
- Family history of eczema or allergies.
- Mother smoking during pregnancy.
- Exposure to second-hand smoke.
- Maternal obesity.
But we don’t fully understand the reasons people develop asthma, and in many people it appears spontaneously. Mothers-to-be with asthma should be reassured that it will not inevitably be passed to their baby.
You could also remind them that their own experience of asthma means they’re more likely to be able to spot any symptoms in their child, and support them as they grow up.
Women may have questions about dietary supplements to reduce the risk of asthma being passed to their baby, such as probiotics, selenium, vitamin E or fish oil. Currently there’s not enough evidence to recommend any of these.
There’s evidence that yoga may improve quality of life for some people with asthma. If stress is a trigger, calming and pregnancy-safe exercise like yoga could reduce asthma symptoms, too.
Asthma UK – asthma.org.uk 0300 222 5800
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