Physical activity during pregnancy may affect lung function in offspring
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A new study presented at the European Respiratory Society International Congress demonstrated a link between lower lung function in infants born to physically inactive mothers compared with those born to physically active mothers.
“Impaired lung function in infancy is associated with increased risk of childhood wheezing and asthma as well as lower lung function later in life,” Hrefna Katrin Gudmundsdottir, pediatrician and PhD student at the University of Oslo, Norway, said during her presentation. “The development of impaired lung function starts in fetal life. Fetal size is protective against childhood asthma by low birthweight, family history of asthma and exposure to maternal smoking and is associated with lower lung function and an increased risk of obstructive lung disease.”
The study included 814 infants (48.8% girls) from the general population-based PreventADALL birth cohort from December 2014 to October 2016. The researchers assessed infants’ available tidal flow volume measures while awake at age 3 months and the mothers’ midpregnancy physical activity data. All mothers completed questionnaires at 18 and 34 weeks regarding their health, lifestyle, socioeconomic factors and nutrition in addition to reporting how often they exercised, for how long and the intensity.
The primary outcome was the ratio of time to peak tidal expiratory flow to expiratory time. The average ratio of time to peak tidal expiratory flow to expiratory time was 0.391.
Of the 290 babies born to physically inactive mothers, 25 (8.6%) were in the group with the lowest lung function, and 22 (4.2%) of the 524 babies born to physically active mothers were in the group with the lowest lung function, for a total of 47 babies (5.8% overall) with low lung function, according to the release.
Lung function was lowest in the 290 infants born to mothers who were physically inactive during pregnancy and highest in the 299 infants born to mothers who were highly physically active during pregnancy had the lowest lung function at age 3 months (0.387 vs. 0.394, respectively; P = .59).
There was no significant association between time to peak tidal expiratory flow to expiratory time as a continuum and maternal physical activity. However, infants born to mothers who were physically inactive during pregnancy had higher odds of having a ratio of time to peak tidal expiratory flow to expiratory time of less than 0.25, which indicates lower lung function, in univariable (OR = 2.15; 95% CI, 1.19-3.92; P = .011) and multivariable (OR = 2.18; 95% CI, 1.18-4.06; P = .013) regression models, according to the results.
“Although there is no clear definition for ‘low’ lung function, studies, including from our own group, have found that infants with a [ratio of time to peak tidal expiratory flow to expiratory time] measurement of less than 0.20 shortly after birth were more likely to have a history of asthma by the age of 10 years. Also, children with lung function in the bottom 50% of the group were both more likely to have current asthma at 10 years and to have a history of asthma,” Gudmundsdottir said in the release.
The researchers will continue to follow the infants involved to assess their lung function progression and its relation to developing respiratory diseases later in childhood.
“We observed a trend that adds to the importance of advising women of child-bearing age and pregnant women about physical activity,” Gudmundsdottir said in the release. “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.”