Are you afraid of having a child with asthma? A new study suggests that the time of the year in which a child is born may have something to do with his/her asthma risk.

Children who celebrate their birthday before the height of cold and flu season have a higher risk of developing childhood asthma than children born in any other time of the year, the study shows. At the same time, the researchers say here are a number of ways to reduce the risk associated with birth timing.

For the study, researchers at Vanderbilt University, in Nashville, analyzed the medical records of 95,000 children and their mothers in Tennessee to determine whether date of birth in relationship with the peak in winter respiratory viruses posed a higher risk for developing early childhood asthma. Birth during the fall months, which is most likely for babies conceived in December or January, was associated with a 30 percent greater risk for developing asthma, study authors report in the first issue of the American Journal of Respiratory and Critical Care Medicine, a publication of the American Thoracic Society. The researchers also found that risk for childhood asthma was higher for babies who suffered from a respiratory tract infection early in life; for those born in the fall months the risk for contracting respiratory viral infections was higher.

The researchers said that the risk of developing asthma from bronchiolitis “is almost certainly influenced by genetic factors.” “However, if this association were due only to genetic factors, there would be a seasonal effect on infection but not on asthma…Instead we have shown that there is variation in the risk of developing asthma by the timing of birth in relationship to the winter virus peak for each year studied. This supports a causal relationship of childhood asthma with the winter virus peak after birth,” the researchers explained.

The number of children with asthma has more than doubled since the 1980s. According to the CDC estimates, about 20 million Americans have asthma, including 9 million children.

“Infant age at the winter virus peak following birth independently predicts asthma development, with the highest risk being for infants born approximately four months prior to the peak, which is represented by birth in the fall months in the Northern hemisphere. Birth during this time conferred a nearly 30 percent increase in odds of developing asthma,” said Tina V. Hartert, M.D., M.P.H., associate professor of medicine and director of the center for Asthma Research at Vanderbilt University, and first author of the study.

Researchers note that for families whose babies are at high risk for developing asthma, timing of birth in the spring months, or avoid infection through administration of a vaccine may significantly reduce their asthma risk.

Asthma is a chronic disease involving the respiratory system in which the airways occasionally constrict, become inflamed, and are lined with excessive amounts of mucus, often as a response to one or more triggers, such as exposure to an environmental stimulant (e.g. an allergen, environmental tobacco smoke, cold or warm air, perfume, pet dander, moist air) or even emotional stress.

Although there is no cure, medication can help control the disease and relieve pressure in the airways during an asthmatic episode.