Asthma in pregnant women: a growing predicament

Asthma is considered to be one of the most common comorbidities for pregnant women, with an increasing prevalence each year. Yet many remain undertreated, and those that do often receive a generalized approach to treatment. How can we ensure a higher standard of care?

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A common issue in pregnancy
Considered to be the most common chronic disease during pregnancy, and with increasing prevalence year to year (3.7% in 1997 to 8.4% in 2001), asthma presents significant clinical and treatment challenges in expectant mothers.1,2 It’s estimated that up to 45% of pregnant women with asthma experience exacerbations during their pregnancy which necessitate medical intervention.2 In milder cases, exacerbations can lead to poor clinical outcomes including low birth weight and preterm delivery, but in more severe instances, they may result in maternal and fetal morbidity and mortality.1,2

Undertreatment is common
Undertreatment of asthma in expectant mothers remains a prevalent issue.3 A US study between 2001–2007 in 38,495 pregnant women with asthma revealed that medications were only filled by 63%, with a quarter of these women using inhaled corticosteroids (ICS) and a further 4% using an ICS/long-acting beta agonist (LABA) combination.4 Similarly, an Australian survey in 2009 reported that only 57% of expectant mothers used reliever medication and nearly a quarter did not use any treatments at all. In contrast, when considering pre-pregnancy medication in the Australian survey, 92.2% of women reported using pharmacological asthma therapies prior to their pregnancy.2,5 Evidently there is a disconnect between asthma treatment use before and during pregnancy. Despite acknowledgement of the potential dangers of asthma in pregnant women, there may be a propensity to stop or reduce asthma therapies due to a belief by the mother or their physician that they threaten the health of the fetus.2,3

The ‘one-third’ rule
The long-standing belief as it relates to pregnancy and asthma is that patients would fall into one of three categories: one third will experience a worsening of symptoms, one third will experience an improvement of symptoms, and one third will experience no change in symptoms. However, recent research contradicts this, with results highlighting that the likelihood of deterioration to the point of exacerbation correlates with the initial severity of asthma.3 In addition, while some mothers’ symptoms may improve in their first trimester, worsening of symptoms is typically reported in the late second trimester, with issues uncommonly occurring in late pregnancy and labor.3 Tailored treatment grounded in an individual woman’s unique situation is therefore critical in the management of asthma in pregnancy.

A multidisciplinary approach
How can we ensure optimal treatment of pregnant women with asthma? Throughout the duration of pregnancy, an expectant mother will interact with a number of healthcare professionals (HCPs) who can help to encourage proactive asthma management and offer self-management education. Pharmacists, nurses, midwives, and primary care physicians can all help to promote a multidisciplinary approach. By gaining understanding of an individual’s treatment beliefs and barriers to adherence, informed conversations and patient education can be facilitated.2 Doing so can help us move away from undertreatment and generalized care, to provide a tailored treatment approach, with the ultimate aim of avoiding negative health outcomes for an expectant mother. Discover more about life with asthma in our Asthma Stories series and stay abreast of the latest in respiratory care with our updates.


1. Shebl E et al. Asthma In Pregnancy in StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing 2019.
2. Murphy VE et al. Breathe (Sheff) 2015; 11(4): 258–267.
3. Giles W and Murphy V. Obstet Med 2013; 6(2): 58–63.
4. Hansen C et al. Matern Child Health J 2013; 17: 1611–1621.
5. Sawicki E et al. NZ J Obstet Gynaecol 2012; 52: 183–188.

November 2019 RESP-41990