A new study says common colds that mothers experience during pregnancy may lead to their child’s development of asthma. Photo by Mike Fritz/PBS NewsHour.

Mothers-to-be can add one more thing to their list of worries. Scientists now say that exposure to the common cold during pregnancy may lead to an increased risk of asthma or allergies in children.

According to a new study published in the February issue of Annals of Allergy, Asthma and Immunology (ACAAI), the more common colds and viral infections a mother experiences during pregnancy, the greater her child’s risk may be to developing asthma or allergies.

These colds and infections shape the baby’s utero environment and can have lasting effects through childhood development.

“We know that allergy and asthma can develop in the womb since genetics play a factor in both diseases,” said ACAAI president and allergist Michael Foggs. “But this study sheds light about how a mother’s environment during pregnancy can begin affecting the child before birth.”

Allergist Mitch Grayson — deputy editor of ACAAI — says that likewise, utero exposure to allergens can increase the risk of childhood allergies to those substances.

“In addition, these same children that had early exposure to allergens, such as house dust and pet dander, had increased odds of becoming sensitized by age five. When dust mites from the mother and child’s mattresses were examined, children with high dust mite exposure yet low bacteria exposure were more likely to be allergic to dust mites than those with low mite exposure and high bacteria contact.”

The study, conducted in Germany, included 513 pregnant women and their 526 children. Questionnaires were completed over the course of pregnancy and through the fifth year of the children’s lives.

ACAAI says asthma and allergies can also be hereditary.