In Australia, 13% of pregnancies are affected by asthma, making asthma the most common medical condition during pregnancy.

In Australia, 13% of pregnancies are affected by asthma, making asthma the most common medical condition during pregnancy.

Asthma, a chronic health condition, in which your airways narrow and swell and produce extra mucus, can cause breathing difficulties, coughing, wheezing, and shortness of breath. With both the hormonal and physical changes occurring during pregnancy due to the expanding uterus, many asthmatic women find their asthma worsens when they are pregnant.
Poorly controlled asthma can negatively impact both mother and baby, increasing the risk of gestational diabetes and pre-eclampsia in the mother, as well as an increased risk of the baby being born prematurely, at a low birth weight or requiring admission to NICU.

Breathing for Life

Between 2013 and 2020, HMRI Asthma and Breathing researchers led by Associate Professor Vanessa Murphy recruited 1200 pregnant women into the Breathing for Life trial – a study of asthma management in pregnancy. 731 of these women and their babies were from the Hunter region.
Key findings from the research in babies show that:

• Mothers with asthma have baby boys with lower lung function at 6 weeks of age – this could affect their lung function trajectory throughout life and their risk of poor lung health later in life.
• Markers of inflammation in the baby’s lungs as early as 6 weeks of age can predict wheeze-related illness (eg bronchiolitis) in the first year of life – this could become a useful tool to identify babies at risk of asthma.
• Immune cells in the cord blood are altered in association with air pollutant exposure in pregnancy – exposure to pollutants from bushfires could contribute to alterations in the baby’s developing immune system
• Longer duration of breastfeeding (more than 6 months vs never) is associated with less wheeze-related illness (eg bronchiolitis) in infancy. Even 1 month of breastfeeding reduced the risk of seeking medical help for wheeze compared to no breastfeeding – Supporting women with asthma to breastfeed could improve lung health in their babies

The burden of bushfire smoke

Bushfires have become one of the biggest environmental threats to human health, with bushfire smoke a mixture of particulate matter and a range of gases such as carbon monoxide, nitrogen dioxide and volatile organic compounds that have a negative impact on human health.
The climate of Australia has meant we see a high occurrence of bushfires and the evidence of climate change will only see this occurrence increase.

Pregnant women and their children, and in particular, pregnant women with asthma are particularly vulnerable to bushfire smoke. There is strong evidence in the general population that exposure to bushfire smoke increases the risk of poor pregnancy outcomes including:

• Stress and depression
• Gestational diabetes
• Increased blood pressure during pregnancy
• Miscarriage
• Respiratory and non-respiratory symptoms
• Preterm birth
• A baby with a low birth weight
• Child mortality in low to middle-income countries

How can pregnant women reduce their risk of bushfire smoke exposure?

• Have asthma? Ensure it is well-controlled. – If smoke is a known trigger use a preventer during bushfire season or if they live in an area where hazard reduction burns are planned.
• Stay indoors where possible. Consider using a HEPA filter and an air-conditioner that recirculates inside air.
• Have a Fire Emergency Plan and ensure a sufficient amount of essential items like medicines and asthma inhalers are on hand.
• Minimise or avoid additional sources of indoor air pollution – this includes candles, wood fires, vacuums without a filter, incense sticks and cigarette smoke – all these sources can increase levels of harmful substances in the air.
• Use air-conditioning or air purifiers – there is good evidence to show that High-Efficiency Particulate Absorbing (HEPA) filters reduce exposure to poor air quality and improve health. Air-conditioners, while not made to filter particles, may still help improve air quality when used to recirculate indoor air when outdoor air quality is poor.
• Avoid exercising outside – During exercise, people increase their air intake 10-20 times over their resting level, therefore during bushfire smoke events, outdoor activity should be avoided or minimised.
• Use a P2/N95 facemask – Face masks are effective to protecting against bushfire smoke exposure. They might be appropriate for those who can’t avoid being outside when air quality is poor.
• Monitor air quality – Follow local air quality data for your area to assist in planning your daily activities.

Researchers from HMRI’s Asthma and Breathing Research Program have worked to create the Asthma in Pregnancy toolkit to provide a centralised source of evidence-based resources to support healthcare professionals involved in the care of pregnant women with asthma, as well as for pregnant women seeking to improve their asthma management skills.
For more information, you can visit the Asthma in Pregnancy Toolkit here.