A University of Alberta-led research team has identified an association between asthma in pregnant women and adverse outcomes for their newborns, including preterm birth, low birth weight and caesarean section delivery.
“For women who are pregnant or planning to get pregnant, it’s important to be aware of their asthma management and see their doctors to connect with resources,” says principal investigator Padma Kaul, professor of medicine and Canadian Institutes of Health Research Sex and Gender Science Chair. “We are also trying to give clinicians information that may be useful in their decision-making.”
In recently published research in The Journal of Allergy and Clinical Immunology in Practice, the team tracked health data (including hospital visits, prescriptions, diagnoses and blood work results) for more than 400,000 pregnancies in Alberta between 2009 and 2018.
Of those expectant mothers, 8.6 per cent or 37,394 had an asthma diagnosis. In those mothers with asthma, seven per cent were experiencing active asthma symptoms, 40 per cent had symptoms within the year before their pregnancy and 52 per cent had been diagnosed earlier in their lives.
The researchers found a 15 per cent higher risk of preterm birth, an 11 per cent higher risk of low birth weight and a 10 per cent higher risk of C-section among the newborns whose mothers had asthma, compared with those who had no asthma diagnosis.
For the first time ever, the researchers examined different asthma types, finding that the relative risk of adverse perinatal outcomes was highest for those with high eosinophil and neutrophil counts in their blood, signs of an active immune response.
They also observed better outcomes in pregnancies where the mothers participated in some prenatal education.
“We know from previous studies that maternal asthma has an impact on the likelihood of whether there’s going to be asthma or allergic airway diseases in the child,” Kaul points out. “What hadn’t been done was to look at the timing of asthma or how specific phenotypes impact perinatal outcomes.”
The research fits perfectly with the Canadian Institutes of Health Research priority to examine the impact of acute asthma care across the lifespan, Kaul points out.
The research team is designing future studies to better understand the impact of medications on both the mothers’ disease and their children’s outcomes. They plan to examine links between environmental factors such as pollution from wildfires and their impact on the incidence of both maternal and early childhood asthma.
“It’s key that we examine these questions longitudinally,” says Kaul. “The biggest strength we have is the access to Alberta population-level data and the pregnancy/birth cohort that we have created for doing these kinds of observational studies.”
In addition to Kaul, the research was led by Subhabrata Moitra, a former U of A postdoctoral student who is now an assistant professor at Ahmedabad University in India; Paige Lacy, professor of medicine; Anamaria Savu, a biostatistician at the Canadian VIGOUR Centre; and colleagues from France and Spain.
This research was facilitated by the infrastructure, training and operating support provided by a partnership between the Women & Children’s Health Research Institute (WCHRI) through the Stollery Children’s Hospital Foundation and the Canada First Research Excellence Fund to One Child Every Child, a child health project based at the University of Calgary. Kaul is academic lead of WCHRI’s Artificial Intelligence + Data Hub.