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Poor asthma control in pregnancy linked to serious adverse outcomes

Maternal asthma exacerbation linked to increased risk of preeclampsia, low birth weight, preterm birth, heart defect and cleft lip

Louise Prime

Wednesday, 27 November 2019

Women who have asthma exacerbation during pregnancy are at increased risk of serious adverse maternal and infant outcomes compared with women with well controlled asthma, research from Canada has shown. A respiratory medicine expert said the results of the study*, published today in the European Respiratory Journal, highlight the importance of carefully maintaining asthma control and managing asthma symptoms during pregnancy.

They cited previous research showing that almost 40% of pregnant women decrease or stop taking asthma medications because of concerns about their safety, and also that poorly controlled asthma might increase asthma severity and the risk of having asthma exacerbation (AE) during pregnancy. But they added that until now, associations between AE during pregnancy and adverse maternal and child health outcomes have not been appropriately investigated, so they designed a population cohort study to look at risks of pregnancy complications, adverse perinatal outcomes, and early childhood respiratory disorders. They analysed data from the Ontario asthma surveillance system and population-level health administrative data, for 103,424 singleton pregnancies in 58,524 women aged 13-45 years, with prevalent asthma.

In this cohort there were 4,455 pregnancies with AE, in 2,663 women with asthma. The researchers reported that compared with women with asthma but no AE during pregnancy, AE was associated with significantly higher odds of preeclampsia (odds ratio, OR 1.30) and pregnancy-induced hypertension (OR 1.17); and of the babies being of lower birth weight (OR 1.14), being pre-term (OR 1.14), or having congenital malformations (OR 1.21).

In addition, children born to women with AE during pregnancy had a significantly increased risk of asthma (OR 1.23) and pneumonia (OR 1.12) during their first five years of life.

The study authors identified no significant interactions between maternal age and smoking for all outcome assessment.

They pointed out that because their study compared women with asthma who experienced exacerbation during pregnancy with those who had asthma but did not have exacerbation during pregnancy, their results denote the impact of AE during pregnancy, as opposed to the impact of asthma.

They concluded: “Our population-based cohort study identified the detrimental effects of AE during pregnancy. … [and] the long-term intergenerational effect of AE during pregnancy by following the same babies up to five years of age.

“Targeting women with asthma during pregnancy and ensuring appropriate asthma management and postpartum follow-up may help to reduce the risk of pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders.”

Professor of Respiratory Medicine at the University of Manchester Jørgen Vestbo, who is chair of the European Respiratory Society’s Advocacy Council, commented on the study: “This highlights the importance of carefully maintaining asthma control and managing asthma symptoms during pregnancy. Pregnant women who have asthma need regular antenatal care to discuss their symptoms and ensure their medication is effective.”


*Abdullah K, Zhu J, Gershon A, et al. Effect of asthma exacerbation during pregnancy in women with asthma: A population-based cohort study. Eur Respir J 2019; DOI:10.1183/13993003.01335-2019.

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