Mother's illness, allergen exposure during pregency may predict child's risk of asthma and allergy

American College of Allergy, Asthma, and ImmunologyFeb 4 2014

Women that are pregnant may want to take extra precaution around those that are sniffling and sneezing this winter. According to a new study published today, the more common colds and viral infections a woman has during pregnancy, the higher the risk her baby will have asthma.

The study, published in the February issue of Annals of Allergy, Asthma and Immunology, found a mother's infections and bacterial exposure during pregnancy affect the in utero environment, thus increasing a baby's risk of developing allergy and asthma in childhood.

"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 Mitch Grayson, MD, Annals deputy editor and fellow of the American College of Allergy, Asthma and Immunology (ACAAI). "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."

Researchers studied 513 pregnant women in Germany, and their 526 children. Questionnaires were completed during pregnancy, when the children were three and 12 months old, and every year up to five-years-old. Of the families, 61 percent had a parent with asthma, hay fever or atopic dermatitis.

According to the ACAAI, asthma and allergy can be hereditary. If both of a child's parents have allergies, the child has a 75 percent chance of being allergic. If one of the parents is allergic, or if a close relative has allergies, the child has a 30 to 40 percent chance of having some form of allergy. If neither parent has allergy, the chance is only 10 to 15 percent.

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

Asthma is the most common potentially serious medical condition to complicate pregnancy, according to the ACAAI. In fact, asthma affects approximately 8 percent of women in their childbearing years. When women with asthma become pregnant, one-third of the patients improve, one-third worsen and one-third remain unchanged.

Women who are or plan on becoming pregnant should continue speaking with their board-certified allergist about treatment options and how to eliminate symptom triggers. More information and a video about allergy and asthma during pregnancy, visit http://www.acaai.org/pregnancy.