Maternal psychological distress during pregnancy affects wheezing in preschool children

Mechanisms such as social, behavioral, and environmental factors during pregnancy that may affect the risk of childhood asthma have been studied, but only few studies have assessed the relationship between maternal psychological distress and childhood wheezing.  Guxens et al performed a population-based study among children from birth to 6 years of age while assessing maternal and paternal psychological distress during pregnancy (J Allergy Clin Immunol 2014; 133(1): 59-67).  This large study of 4,848 children was embedded within the Generation R study, a population-based prospective cohort from fetal life onwards in Rotterdam, The Netherlands.  Maternal and paternal distress data was collected at 20 weeks gestation and again at 2 and 6 months, and 3 years after delivery by using the Brief Symptom Inventory questionnaire. Wheezing was annually assessed in the children up to 4 years of age. Physician diagnosed ever asthma was reported by parents at age 6 years. 

The authors point out that the association between maternal psychological distress during pregnancy and childhood asthma might be explained by developmental adaptations of the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, the lung structure and function, and immune responses in the children but also other mechanisms such as social, behavioral, or environmental factors.  To assess the role of different mechanisms, the authors assessed the associations both for the mother (unique intrauterine mechanism) and father (social, behavioral, or environmental factors), all taking into account many socioeconomic and lifestyle variables, and maternal psychological distress after the child was born. Children ultimately included in the analysis were more frequently from parents with a higher education level, and their parents had less psychological distress during pregnancy compared to those lost in follow-up. 

Guxens concludes that mothers with psychological distress during pregnancy had increased odds of overall wheezing in their children from 1 to 4 years of life, or of asthma at 6 years of age, compared to mothers that did not.  This result was similar in children of mothers with a history of asthma and atopy, compared to those without.  The authors go on to show that the robust result is independent of paternal psychological distress during pregnancy and maternal and paternal psychological distress after delivery.  These results suggest a direct intrauterine programming effect of maternal psychological distress on respiratory morbidity. To study these potential underlying biological mechanisms, markers of stress (diurnal cortisol rythm) and changes in the immune system (types of lymphocytes) could be measured. Our study has these data in a limited number of children only. Data for a genetic underlying mechanism, including interaction with environmental factors, are available and will be explored in the future.