Women with asthma struggle more to become pregnant, research suggests. But using long-acting steroid inhalers removed the problem, scientists found.
And they were 40 % more likely to be classed as ‘infertile’ – defined as having unsuccessfully tried for a baby for more than a year.
Long-acting steroid inhalers – brown inhalers used on a regular basis – resulted in asthmatic patients conceiving as quickly as healthy women.
But women who only used blue inhalers – the emergency devices which remove symptoms in the case of an asthma attack – saw no benefit to their conception speed.
The scientists from the University of Adelaide, writing in the European Respiratory Journal, said the inflammation that triggers asthma is the most likely explanation for a reduction in fertility. They believe the inflammation may also affect the reproductive system.
Lead researcher Dr Luke Grzeskowiak said: ‘There is plenty of evidence that maternal asthma has a negative impact on the health of pregnant mothers and their babies, and so our general advice is that women should take steps to get their asthma under control before trying to conceive.
‘What we don’t yet know is exactly how asthma or asthma treatments lead to fertility problems. As well as affecting the lungs, asthma could cause inflammation elsewhere in the body, including the uterus.
‘It could also affect the health of eggs in the ovaries. Inhaled corticosteroids suppress the immune system, whereas short-acting asthma treatments do not alter immune function.
‘In women who are only using relievers it’s possible that, while their asthma symptoms may improve, inflammation may still be present in the lungs and other organs in the body.’
Dr Erika Kennington, head of research of Asthma UK, said: ‘This study shines a light on how vital it is that people with asthma take their preventative brown inhaler.
‘We’d advise women with asthma who are trying for a baby, to ensure they get their asthma under control and to speak to their doctor if they don’t have a preventer inhaler.’ Dr Grzeskowiak added: ‘Five to ten per cent of all women around the world have asthma and it is one of the most common chronic medical conditions in women of reproductive age.
‘Several studies have identified a link between asthma and female infertility – but the impact of asthma treatments on fertility has been unclear.
‘Studying the effect of asthma treatments in women who are pregnant or trying to get pregnant is important as women often express concerns about exposing their unborn babies to potentially harmful effects of medications.’