Prenatal maternal bereavement and risk of eating disorders in infants and toddlers: a population-based cohort study

Background: Prenatal stress has been associated to a number of neuropsychiatric diseases but its role on the development of eating disorders (ED) remains unknown. Infants and toddlers with feeding or eating disorders are also at an increased risk of such diseases in later childhood and adolescence. We aimed to examine whether prenatal stress following maternal bereavement is associated with ED in infants and toddlers. Methods: This population-based cohort study included children born from 1977 to 2008 in Denmark (N = 2,127,126) and from 1977 to 2006 in Sweden (N = 2,974,908). Children were categorized as exposed if they were born to mothers who lost a close relative one year prior to or during pregnancy and were categorized as unexposed otherwise. They were followed until the age of 3 for a first diagnosis of ED. Poisson regression models were used to examine incidence rate ratio (IRR) between the exposed and the unexposed cohort. Results: A total of 9,403 ED cases were identified and 179 of whom were in the exposed cohort. Offspring born to mothers bereaved by loss of a core family member (older child or spouse) within the six months before pregnancy had a higher risk of ED than the unexposed offspring (IRR: 1.63, 95 % confidence intervals (CI): 1.07-2.47). In stratified analyses, bereavement during the six months before pregnancy was associated with an increased risk of ED in boys (IRR: 2.21, 95 % CI: 1.28-3.82), but not in girls (IRR: 1.18, 95 % CI: 0.61-2.27). Discussion: This is the first population-based study to explore the association between prenatal stress and the risk of ED in infants and toddlers within two Nordic countries. This study added new evidence of early life stress for etiology of ED while the potential mechanism still needs further studies. Conclusions: Prenatal stress following maternal bereavement by loss of a core family member is associated with an increased risk of ED among infants and toddlers. The six months before conception may be a susceptible time window, especially for boys.