Asthma is a prevalent disease among children, accounting for numerous emergency room visits, and unfortunately, a significant cause of morbidity. Although asthma incidence has increased over the past few decades, variations between countries, environmental factors and the use of certain medications have created a flurry of research dedicated to the disease and the understanding of its etiology.

Epidemiological studies have suggested that they key time period for childhood allergies and asthma development occurs between conception and early childhood, and prenatal drug use has also been implicated. In a letter to the Editor in The Journal of Allergy & Clinical Immunology, Mulder and colleagues assessed the association between the use of acid-suppressive drugs during pregnancy and the risk of developing childhood asthma using a crossover study. As gastrointestinal symptoms in pregnancy are fairly common, proton pump inhibitors (PPIs), histamine 2 receptor antagonists (H2ra) and other antacids have been known to be effective. Understanding that the development of asthma is a complex interaction between genetic and environmental factors, researchers used a general practitioners research database to identify children with a drug-treated asthma diagnosis between the years 2006 and 2010 that were matched with a sibling without asthma. Researchers conducted analyses based on exposure of anti-suppressive drugs, drug class (e.g. PPIs, H2ra) and trimester.

Of the 3,748 children studied, half with asthma and the other used as a control group, 22% of the children with asthma had mothers who were exposed to an acid-suppressive drug during their pregnancy compared to 20% in the control group. This data suggests that exposure to acid-suppressive drugs during pregnancy presents an increased chance in developing childhood asthma. Upon further analyses, mothers who used acid-suppressive drugs during the third trimester increased the odds of their child developing childhood asthma. These findings support evidence that exposure to acid-suppressive drugs during pregnancy is associated with childhood asthma. Although more research is needed to understand the exact mechanisms, one hypothesis suggests that neutralized gastric levels prevent adequate digestion of antigens in the mother’s stomach. The antigens, if not degraded can create sensitization of the immune system and cross the placenta creating likelihood for allergic sensitization of the fetus.