Exercise during pregnancy tied to better lung function in babies

Infants born to mothers who were inactive during pregnancy were more likely to have low lung function compared with those whose mothers were active while pregnant, according to the PreventADALL study presented at ERS 2021.

“Previous studies have shown that individuals with low lung function in infancy have higher risk of asthma, other obstructive lung diseases, and lower lung function later in life,” said Dr Hrefna Katrin Gudmundsdottir from University of Oslo in Oslo, Norway. “Therefore, exploring factors that can be associated with lung function in infants is important.”

“If being physically active during pregnancy could reduce the risk of impaired infant lung function, it would be a simple, low-cost way to improve the respiratory health of offspring,” she pointed out.

The population-based birth cohort study included 814 infants (49 percent girls) with available data on tidal flow volume measured at 3 months in the awake state, whose mothers had self-reported data available on physical activity during mid-pregnancy (around 18 weeks). The women were categorized as inactive, fairly active, or very active based on the frequency, duration, and intensity of exercise during mid-pregnancy. [ERS 2021, abstract OA1294]

Low lung function at age 3 months, as indicated by the ratio of time to peak tidal expiratory flow to expiratory time (tPTEF/tE), was more common in infants born to mothers who were inactive during pregnancy compared with mothers who were fairly or very active while pregnant.

The average tPTEF/tE of infants born to inactive mothers (n=290) was lower than those whose mothers were very active (n=299) during pregnancy (mean, 0.387 vs 0.394).

“In our study, we found that babies born to inactive mothers were more likely to be in the group with the lowest lung function compared to babies born to active mothers,” reported Gudmundsdottir.

Among the 290 infants born to inactive mothers, 8.6 percent landed in the stratum with the lowest lung function compared with just 4.2 percent among the 524 infants of active mothers.

While there was no significant association between maternal physical activity and tPTEF/tE measured as a continuous variable, infants of inactive mothers were significantly more likely to have a tPTEF/tE below 0.25 than those born to fairly or very active mothers (adjusted odds ratio [OR], 2.18; p=0.013). The increased risk of having low lung function remained even after adjusting for maternal age, parity, education, pre-pregnancy BMI, parental atopy, and exposure to nicotine in utero.

“We observed a trend that adds to the importance of advising women of child-bearing age and pregnant women about physical activity. However, there may be factors that affect both maternal physical activity and lung function in offspring that we have not accounted for and could affect the results and so more research is needed,” said Gudmundsdottir.

“We also hope to explore associations between maternal physical activity and asthma, allergies and other non-communicable diseases in the future,” she added.

“It’s also worth keeping in mind that the single most important thing that mothers can do for their own health and that of their baby is to ensure that they do not smoke or use other tobacco products before, during, and after pregnancy. A smoke-free home has the biggest impact on lung function and health in childhood and later life,” advised Gudmundsdottir.