Prenatal Maternal Bereavement and Its Association With Intellectual Disability in the Offspring

OBJECTIVE: This study aimed to examine the association of a mother’s loss of a close relative before or during pregnancy with intellectual disability (ID) in the offspring. METHODS: We performed a nationwide population-based cohort study based on Danish national registries. All live-born singletons born in Denmark during the 1978–2016 period (n = 2,216,601) were followed up starting from birth to 38 years of age. Log-linear Poisson regression was used to estimate the association between maternal bereavement (the death of an older child, a partner, or a parent 1 year before or during pregnancy) and the risk of ID in the offspring. RESULTS: Maternal bereavement during or before pregnancy was associated with an increased risk of ID (incidence rate ratio [IRR] = 1.15; 95% confidence interval [CI] = 1.04–1.28). The risk of ID was increased by 27% when maternal bereavement occurred during pregnancy (IRR = 1.27; 95% CI = 1.08–1.49). When stratifying on the child’s sex, we also observed an increased risk of ID associated with maternal bereavement during pregnancy both for male (IRR = 1.25; 95% CI = 1.02–1.53) and for female (IRR = 1.31; 95% CI = 1.02–1.69), respectively. The IRRs for unnatural death of a relative were also elevated (IRR = 1.22; 95% CI = 0.91–1.64) in general, although the difference was not statistically significant. CONCLUSIONS: Our findings suggest that prenatal stress due to maternal loss of a close relative may increase the risk of offspring’s ID of both sexes, in particular when the loss happened during pregnancy.