Prenatal Stress and Risk of Asthma Hospitalization in the Offspring: A Swedish Population-Based Study

Objective: Recent research suggested that maternal stress and anxiety increase the risk of asthma and eczema in the offspring. In this study, we aimed to study whether maternal exposure to death of a spouse or a child is associated with risk of asthma hospitalization in the offspring using a very large population-based cohort. Methods: In a cohort of 3.2 million births in Sweden between January 1, 1973, and December 31, 2004, mothers were considered exposed if their spouse or child died up to 6 months before or during pregnancy. Offspring were followed up from birth to their death, migration, first hospitalization with asthma, or December 31, 2006, whichever came first; hospital admissions were identified by linkage of several national Swedish registers. Log-linear Poisson regression was used for data analysis. Results: Overall, the risk of offspring asthma was increased with any prenatal exposure to bereavement in any exposure period (adjusted relative risk [RR] = 1.20 [95% confidence interval {CI} = 1.03-1.39]). The risk was higher when the exposure period was restricted to pregnancy only (adjusted RR = 1.43 [95% CI = 1.06-1.92]). Furthermore, the risk of asthma was increased in relation to death of a spouse during pregnancy (adjusted RR = 1.59 [95% CI = 1.10-2.30]). Conclusions: These findings suggest that prenatal exposure to severe life events increases the risk of hospitalization for asthma in the offspring. Fetal programming may be a plausible explanation for the association.