As if mothers didn’t have enough to worry about when it comes to what they put in their bodies during pregnancy, a new study published in the journal Annals of Allergy, Asthma and Immunology shows that something as simple as the common cold or case of the sniffles may increase the chances a child will be born with asthma.

It’s been well known that a mother’s environment can greatly influence the health of the newborn baby, but now researchers from the American College of Allergy, Asthma, and Immunology (ACAAI) suggest that allergens and airborne bacteria can affect the development of the growing fetus, putting it at greater risk to develop an allergy — a risk also dependent on parent genetics — along with asthma.

The ACAAI team investigated 513 pregnant women in Germany and their 526 children. Researchers questioned the mothers about their family history with asthma and allergy at several points after delivery — three months, one year, and every subsequent year until the child was 5 years old. Sixty-one percent of the children had at least one parent with asthma, hay fever, or atopic dermatitis.

Largely, the children whose mothers had been exposed to high-allergen environments were more likely to be born with conditions highly sensitive to those environments. "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," said allergist Dr. Mitch Grayson, deputy editor of the journal and fellow of the ACAAI, in a statement.

Certain places around the families’ homes showed greater potential to harm developing immune systems as well, Grayson pointed out, such as children’s mattresses. Those “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,” he said.

Allergies, asthma included, are characterized by the immune system’s hypersensitivity to otherwise harmless substances. For asthmatics, allergens inflame the person’s airways and restrict breathing. Roughly eight percent of pregnant women suffer from asthma during gestation, according to ACAAI figures. Complications improve, worsen, and show no change with equal frequency.

While the link isn’t necessarily new — science has known for years that mothers should carefully restrict what they ingest and inhale, such as their diet and first- and secondhand cigarette smoke — scientists now have a better understanding of the specific role a pregnancy’s context can have on fetal development. Experts typically advise women who are pregnant or plan on becoming pregnant to consult with an allergy specialist before they receive treatment.

"We know that allergy and asthma can develop in the womb since genetics play a factor in both diseases," Dr. Michael Foggs, ACAAI’s president, said in the release. For instance, children whose parents both have allergies are 75 percent more likely to develop one themselves. When only one parent has an allergy, the risk drops to 40 percent, and when neither parent is allergic to anything, the child’s chances are 10 to 15 percent. "But this study sheds light about how a mother's environment during pregnancy can begin affecting the child before birth,” he added.

Source: Illi S, Weber J, Zutavern A. Perinatal influences on the development of asthma and atopy in childhood. Annals of Allergy, Asthma and Immunology. 2014.