Autumn is a wonderful time to welcome a baby into the world: The leaves are falling, the air is crisp and the holidays are just around the corner. But there may be an unexpected downside to an autumn delivery: A study by researchers at Vanderbilt University shows that babies born during the months preceding flu season are thirty percent more likely to develop asthma during childhood.

The researchers tracked more than ninety-five-thousand Tennessee children from birth through early childhood. Those who suffered from viral respiratory infections during infancy were most likely to eventually develop asthma. The risk was greatest for babies who were four months old during the peak of the winter virus season.

The scientists aren’t completely sure why autumn babies, in particular, are more susceptible to developing childhood asthma. But they suspect exposure to a winter virus might compound certain genetic factors that increase the risk of respiratory problems later in life. Their findings were published in a recent issue of the American Journal of Respiratory and Critical Care Medicine.

It may be impossible to prevent your child from catching a virus, as the scientists say more than seventy percent of infants develop a respiratory infection during the winter months. But parents of autumn babies can take several precautions to prevent illness during flu season, including frequent hand-washing and staying up-to-date on vaccines. Staying safe will ensure that parents and babies all breathe a bit easier during this year’s flu season.