BackgroundMaternal depression is a serious condition that effects up to 1 in 7 pregnancies. Despite evidence linking maternal depression to pregnancy complications and adverse fetal outcomes, there remain significant gaps in its identification and treatment. More work is needed to define the specific timing and severity of depression that most urgently requires intervention, where feasible, to protect maternal health and the developing fetus. ObjectiveTo examine whether the timing and severity of maternal depression and/or anxiety during pregnancy effects child executive functioning at age 4.5 years. Executive functioning in the pre-school years is a strong predictor of both school readiness and long term quality of life. Study DesignThis longitudinal observational pregnancy cohort study included a sample of 323 mother-child dyads taking part in the Ontario Birth Study, an open pregnancy cohort in Toronto, Ontario, Canada. Maternal symptoms of depression and anxiety were assessed at 12-16 and 28-32 weeks of pregnancy, and at the time of child testing at age 4.5 years, using the 4-item Patient Health Questionnaire. Child executive functioning was measured during a home visit using standardized computerized administration of the Flanker test (a measure of attention) and the Dimensional Change Card Sort (a measure of cognitive flexibility). Stepwise linear regressions, controlling for possible confounding variables, were used to assess the predictive value of continuous measures of maternal depression and/or anxiety symptoms at each assessment time on the Flanker and Dimensional Change Card Sort. Post-hoc general linear models assessed whether maternal depression severity categories (no symptoms, mild symptoms, probable major depressive disorder) were helpful in identifying children-at-risk. ResultsAcross all children, after controlling for potential confounds, greater maternal depressive symptoms at weeks 12-16 of pregnancy predicted worse performance on both the Flanker test (ΔR2=0.058, p < .001) and the Dimensional Change Card Sort (ΔR2 = 0.017, p = 0.018). Post-hoc general linear modelling further demonstrated that the children of mothers meeting screening criteria for major depression in early pregnancy scored 11.3 % lower on the Flanker test, and 9.8 % lower on the Dimensional Change Card Sort, than did children exposed to no maternal depressive symptoms in early pregnancy. Mild depressive symptoms had no significant effect on executive function scores. There was no significant effect of anxiety symptoms or maternal anti-depressant use in early pregnancy, nor of pandemic conditions or maternal symptoms in later pregnancy or at the time of child testing on either the Flanker or Dimensional Change Card Sort results. ConclusionThis is the first study to demonstrate that during weeks 12-16 of pregnancy, fetal exposure to maternal major depression, but not milder forms of depression, associates with impaired executive functioning in the pre-school years. Child executive functioning is critical for school readiness and predicts long-term quality of life. This emphasizes an urgent need to improve the recognition and treatment of maternal major depression, particularly in early pregnancy, to limit its negative effects on the patient and on child cognitive development.
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