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Early life adversity and insecure attachment style are known risk factors for perinatal depression. The biological pathways linking these experiences, however, have not yet been elucidated. We hypothesized that overlap in patterns of DNA methylation in association with each of these phenomena could identify genes and pathways of importance. Specifically, we wished to distinguish between allostatic-load and role-transition hypotheses of perinatal depression. We conducted a large-scale analysis of methylation patterns across 5 × 10 6 individual CG dinucleotides in 54 women participating in a longitudinal prospective study of perinatal depression, using clustering-based criteria for significance to control for multiple comparisons. We identified 1580 regions in which methylation density was associated with childhood adversity, 3 in which methylation density was associated with insecure attachment style, and 6 in which methylation density was associated with perinatal depression. Shorter telomeres were observed in association with childhood trauma but not with perinatal depression or attachment insecurity. A detailed analysis of methylation density in the oxytocin receptor gene revealed similar patterns of DNA methylation in association with perinatal depression and with insecure attachment style, while childhood trauma was associated with a distinct methylation pattern in this gene. Clinically, attachment style was strongly associated with depression only in pregnancy and the early postpartum, whereas the association of childhood adversity with depression was time-invariant. We concluded that the broad DNA methylation signature and reduced telomere length associated with childhood adversity could indicate increased allostatic load across multiple body systems, whereas perinatal depression and attachment insecurity may be narrower phenotypes with more limited DNA methylation signatures outside the CNS, and no apparent association with telomere length or, by extension, allostatic load. In contrast, the finding of matching DNA methylation patterns within the oxytocin receptor gene for perinatal depression and attachment insecurity is consistent with the theory that the perinatal period is a time of activation of existing attachment schemas for the purpose of structuring the mother-child relationship, and that such activation may occur in part through specific patterns of methylation of the oxytocin receptor gene.

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Purpose The transition to motherhood is a time of elevated risk for clinical depression. Dispositional optimism may be protective against depressive symptoms; however the arrival of a newborn presents numerous challenges that may be at odds with initially positive expectations, and which may contribute to depressed mood. We have explored the relative contributions of antenatal and postnatal optimism regarding maternity to depressive symptoms in the postnatal period. Methods 98 pregnant women underwent clinician interview in the third trimester to record psychiatric history, antenatal depressive symptoms, and administer a novel measure of optimism towards maternity. Measures of depressive symptoms, attitudes to maternity, and mother-to-infant bonding were obtained from 97 study completers at monthly intervals through three months postpartum. Results We found a positive effect of antenatal optimism, and a negative effect of postnatal disconfirmation of expectations, on depressive mood postnatally. Postnatal disconfirmation, but not antenatal optimism, was associated with more negative attitudes toward maternity postnatally. Antenatal optimism, but not postnatal disconfirmation, was associated with reduced scores on a mother-to-infant bonding measure. The relationships between antenatal optimism, postnatal disconfirmation of expectations, and postnatal depression held true among primigravidas and multigravidas, as well as among women with prior histories of mood disorders, although antenatal optimism tended to be lower among women with mental health histories. Conclusions We conclude that cautious antenatal optimism, rather than immoderate optimism or frank pessimism, is the approach that is most protective against postnatal depressive symptoms, and that this is true irrespective of either mood disorder history or parity. Factors predisposing to negative cognitive assessments and impaired mother-to-infant bonding may be substantially different than those associated with depressive symptoms, a finding that merits further study.