The link between mom's stress and baby's asthma

Can maternal stress increase the risk for asthma in the child? The answer appears to be yes. A number of studies over the past few years have demonstrated that chronic stress during pregnancy significantly increases the risk of childhood asthma.

Asthma is an important health problem because it is the most common chronic disease of childhood. Direct and indirect medical costs exceed $1 billion annually. It is also the most common cause of school absenteeism. Despite much research, the causes of childhood asthma remain a mystery. The Centers for Disease Control and Prevention have stated that the societal impact of childhood asthma is significant and that better efforts are need to control it.

Asthma is the result of the body overreacting to allergens. It results in a narrowing of the airways in the lungs. Common symptoms are wheezing, shortness of breath and coughing. Although most cases of asthma can be controlled with medications and lifestyle changes, sometimes asthma attacks can be life-threatening. It is a serious medical condition and, in children, it is happening more often.

There is growing evidence that the lifestyle of the mother during pregnancy can have an effect on the health of the child. For asthma, stress during pregnancy increases the risk of childhood asthma.

In adults and children, stress and anxiety can make asthma worse. Research suggests that the effect of chronic stress and anxiety on the adrenal system negatively affects how the immune system functions, resulting in worsening asthma symptoms. However, could a stressed adrenal system in a mother increase the risk of asthma in the unborn child? A recent publication in the journal of Allergy and Clinical Immunology demonstrated a strong correlation between maternal stress and the risk of childhood asthma.

In this study, 5,810 children were followed for 71/2 years. Stress levels were measured in the mothers several times during their pregnancies. The incidence of asthma was more than 50 percent higher in children whose mothers experienced chronic stress during pregnancy compared to those mothers who had low stress.

How is this possible? Stress hormones like cortisol can cross the placenta into a developing fetus. We also know that these hormones can exert a significant positive or negative effects. Fetal white blood cells are very sensitive to cortisol. As a result, cortisol may preprogram the immune system to overreact to allergens, resulting in childhood asthma.

Stress today can be severe. Although it is difficult to limit stress, there are some pregnancy-safe therapies that can reduce stress and cortisol levels: Have a regular massage; it's a wonderful way to reduce stress. Walking in nature, deep breathing, yoga, tai chi and meditation also reduce stress and promote health.

Most of our chronic medical conditions, like asthma, are related to lifestyle. Fortunately, lifestyle is something we can change.

• Patrick B. Massey, M.D., Ph.D is medical director for complementary and alternative medicine for the Alexian Brothers Hospital Network.