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Asthma attacks in pregnancy pose risk to mother and baby, large study shows

Women who have severe asthma symptoms during pregnancy have a higher risk of complications, such as pre-eclampsia, as well as being more likely to have a premature birth, research shows.

A Canadian study of more than 100,000 pregnancies also showed a greater risk of low birth weight and congenital abnormalities in babies born to mothers who had severe asthma symptoms during pregnancy.

Those who were having asthma attacks were 30% more likely to suffer with pre-eclampsia and around 17% more likely to suffer with high blood pressure during pregnancy compared with pregnant women whose disease was well-controlled.

Children’s risk of asthma up to the age of five years was 23% higher if their mother had experienced severe asthma symptoms in pregnancy, and their risk of pneumonia was around 12% higher, the European Respiratory Journal study showed.

Study leader Dr Kawsari Abdullah, research fellow at the Children’s Hospital of Eastern Ontario, said a large proportion of women with asthma are known to reduce or stop their asthma medication during pregnancy yet the results showed that uncontrolled asthma was the greater risk.

‘Asthma is the most common chronic disease in pregnant women, affecting 8-13% of pregnant women worldwide.

‘If asthma is poorly controlled, patients can suffer with severe symptoms such as wheezing, coughing, or feeling breathless or tight-chested.’

She added: ‘Previous research has shown that one out of every three pregnant women with asthma will suffer severe symptoms, so we need to understand what this means for women and their babies.’

In all there were 4,455 pregnancies in 2,663 women who experienced severe symptoms while pregnant defined as five visits to the doctor, an emergency department attendance or hospital admission due to their asthma symptoms.

Dr Dermot Ryan, retired GP and honorary clinical research fellow at the University of Edinburgh, said the study underlined the importance of careful asthma control in pregnant women.

‘Pregnancy does strange things to the immune system in women – in many it disappears altogether in others it stays the same and in a number it becomes more difficult to control, and it is this latter group which have the exacerbations.’

He added that the authors had noted it was difficult to separate the cause of asthma exacerbation from adverse outcomes including smoking history and deprivation.

‘What is certain is that uncontrolled asthma with exacerbations will add to the insults already received by the unborn child in utero almost certainly making bad situations worse.’