Does prenatal stress increase the risk for childhood asthma?

Abstract

The prevalence of childhood asthma has dramatically risen in the past decade and already exceeds 10% in many western countries. Several studies have linked prenatal maternal stress to the development of asthma in children. Yet, these studies are correlational, confounded, do not limit the time of stress to the prenatal period and thus cannot prove causality. The 2006 conflict between Hezbollah and Israel created a unique natural experiment that neutralized most of the potential confounding parameters and confined the time of experienced stress. In a moderately sized study (n=92), we have found that the prevalence of asthma more than tripled in children whose mothers were pregnant and lived under massive missile attack during the war (high-stress group) as compared to children whose mothers were pregnant a year before/after the war or lived in areas not under missile attack (2*2 design). In addition, birth weight, a potential mediator, was more than 300 gr lower in the high-stress group. These findings stress the importance of psychological interventions during pregnancy as prophylactic measures for asthma.