Intergenerational Transmission of Maternal Childhood Maltreatment Exposure: Implications for Fetal Brain Development

Exposure to traumatic events in childhood predicts cortisol production among high risk pregnant women

Childhood exposure to traumatic events has a profound and disruptive impact on mental and physical health, including stress physiology. In the current study, we evaluate 90 pregnant women at risk for preterm delivery and assess the association between history of exposure to traumatic events and hair cortisol concentrations, an integrated measure of cortisol production. Exposure to more traumatic events in childhood and in adulthood independently predicted elevated hair cortisol concentrations in pregnancy. Notably, the impact of childhood exposure to traumatic events remained after accounting for more proximal traumatic events in adulthood. Further, there was a significant interaction between childhood and adult exposures. Traumatic experiences in adulthood were more strongly associated with hair cortisol concentrations among mothers with a history of greater childhood trauma. Findings suggest that not only do proximal adult exposures impact HPA-axis functioning during pregnancy, but that childhood traumatic experiences have persisting consequences for HPA-axis functioning during pregnancy. Maternal HPA-axis dysregulation in pregnancy has consequences for both maternal health and for fetal development. Therefore, we consider prenatal maternal HPA-axis functioning as a potential biological pathway underlying intergenerational consequences of childhood trauma.

Association of Prenatal Maternal Depression and Anxiety Symptoms With Infant White Matter Microstructure

IMPORTANCE

Maternal depression and anxiety can have deleterious and lifelong consequences on child development. However, many aspects of the association of early brain development with maternal symptoms remain unclear. Understanding the timing of potential neurobiological alterations holds inherent value for the development and evaluation of future therapies and interventions.

OBJECTIVE

To examine the association between exposure to prenatal maternal depression and anxiety symptoms and offspring white matter microstructure at 1 month of age.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study of 101 mother-infant dyads used a composite of depression and anxiety symptoms measured in mothers during the third trimester of pregnancy and measures of white matter microstructure characterized in the mothers' 1-month offspring using diffusion tensor imaging and neurite orientation dispersion and density imaging performed from October 1, 2014, to November 30, 2016. Magnetic resonance imaging was performed at an academic research facility during natural, nonsedated sleep.

MAIN OUTCOMES AND MEASURES

Brain mapping algorithms and statistical models were used to evaluate the association between maternal depression and anxiety and 1-month infant white matter microstructure as measured by diffusion tensor imaging and neurite orientation dispersion and density imaging findings.

RESULTS

In the 101 mother-infant dyads (mean [SD] age of mothers, 33.22 [3.99] years; mean age of infants at magnetic resonance imaging, 33.07 days [range, 18-50 days]; 92 white mothers [91.1%]; 53 male infants [52.5%]), lower 1-month white matter microstructure (decreased neurite density and increased mean, radial, and axial diffusivity) was associated in right frontal white matter microstructure with higher prenatal maternal symptoms of depression and anxiety. Significant sex × symptom interactions with measures of white matter microstructure were also observed, suggesting that white matter development may be differentially sensitive to maternal depression and anxiety symptoms in males and females during the prenatal period.

CONCLUSIONS AND RELEVANCE

These data highlight the importance of the prenatal period to early brain development and suggest that the underlying white matter microstructure is associated with the continuum of prenatal maternal depression and anxiety symptoms.

Intergenerational transmission of trauma effects: putative role of epigenetic mechanisms

This paper reviews the research evidence concerning the intergenerational transmission of trauma effects and the possible role of epigenetic mechanisms in this transmission. Two broad categories of epigenetically mediated effects are highlighted. The first involves developmentally programmed effects. These can result from the influence of the offspring's early environmental exposures, including postnatal maternal care as well as in utero exposure reflecting maternal stress during pregnancy. The second includes epigenetic changes associated with a preconception trauma in parents that may affect the germline, and impact fetoplacental interactions. Several factors, such as sex-specific epigenetic effects following trauma exposure and parental developmental stage at the time of exposure, explain different effects of maternal and paternal trauma. The most compelling work to date has been done in animal models, where the opportunity for controlled designs enables clear interpretations of transmissible effects. Given the paucity of human studies and the methodological challenges in conducting such studies, it is not possible to attribute intergenerational effects in humans to a single set of biological or other determinants at this time. Elucidating the role of epigenetic mechanisms in intergenerational effects through prospective, multi-generational studies may ultimately yield a cogent understanding of how individual, cultural and societal experiences permeate our biology.

Prenatal Immune and Endocrine Modulators of Offspring's Brain Development and Cognitive Functions Later in Life

Milestones of brain development in mammals are completed before birth, which provide the prerequisite for cognitive and intellectual performances of the offspring. Prenatal challenges, such as maternal stress experience or infections, have been linked to impaired cognitive development, poor intellectual performances as well as neurodevelopmental and psychiatric disorders in the offspring later in life. Fetal microglial cells may be the target of such challenges and could be functionally modified by maternal markers. Maternal markers can cross the placenta and reach the fetus, a phenomenon commonly referred to as “vertical transfer.” These maternal markers include hormones, such as glucocorticoids, and also maternal immune cells and cytokines, all of which can be altered in response to prenatal challenges. Whilst it is difficult to discriminate between the maternal or fetal origin of glucocorticoids and cytokines in the offspring, immune cells of maternal origin—although low in frequency—can be clearly set apart from offspring's cells in the fetal and adult brain. To date, insights into the functional role of these cells are limited, but it is emergingly recognized that these maternal microchimeric cells may affect fetal brain development, as well as post-natal cognitive performances and behavior. Moreover, the inheritance of vertically transferred cells across generations has been proposed, yielding to the presence of a microchiome in individuals. Hence, it will be one of the scientific challenges in the field of neuroimmunology to identify the functional role of maternal microchimeric cells as well as the brain microchiome. Maternal microchimeric cells, along with hormones and cytokines, may induce epigenetic changes in the fetal brain. Recent data underpin that brain development in response to prenatal stress challenges can be altered across several generations, independent of a genetic predisposition, supporting an epigenetic inheritance. We here discuss how fetal brain development and offspring's cognitive functions later in life is modulated in the turnstile of prenatal challenges by introducing novel and recently emerging pathway, involving maternal hormones and immune markers.

A Meta-Analysis of Maternal Prenatal Depression and Anxiety on Child Socioemotional Development

OBJECTIVE

Observed associations between maternal prenatal stress and children's socioemotional development have varied widely in the literature. The objective of the current study was to provide a synthesis of studies examining maternal prenatal anxiety and depression and the socioemotional development of their children.

METHOD

Eligible studies through to February 2018 were identified using a comprehensive search strategy. Included studies examined the association between maternal prenatal depression or anxiety and the future development of their children's socioemotional development (eg, difficult temperament, behavioral dysregulation) up to 18 years later. Two independent coders extracted all relevant data. Random-effects meta-analyses were used to derive mean effect sizes and test for potential moderators.

RESULTS

A total of 71 studies met full inclusion criteria for data analysis. The weighted average effect size for the association between prenatal stress and child socioemotional problems was as follows: odds ratio (OR) = 1.66 (95% CI = 1.54-1.79). Effect sizes were stronger for depression (OR = 1.79; 95% CI = 1.61-1.99) compared to anxiety (OR = 1.50; 95% CI = 1.36-1.64). Moderator analyses indicated that effect sizes were stronger when depression was more severe and when socio-demographic risk was heightened.

CONCLUSION

Findings suggest that maternal prenatal stress is associated with offspring socioemotional development, with the effect size for prenatal depression being more robust than for anxiety. Mitigating stress and mental health difficulties in mothers during pregnancy may be an effective strategy for reducing offspring behavioral difficulties, especially in groups with social disadvantage and greater severity of mental health difficulties.

Secure attachment style appears to compensate for the effect of prenatal maternal distress regarding difficult infant temperament development

Objective: Secure attachment style is a known protective factor regarding psychopathological development. The infant's attachment style, which is developed during the first two years of life, is therefore considered a moderating factor on the association between prenatal maternal distress and child temperament development which has repeatedly been reported in previous studies. Method: In this longitudinal study on a new sample of 51 mother-child-dyads, reported maternal distress and maternal empathy were assessed during pregnancy. Infant temperament and motor development were assessed at 12 months, while additionally controlling for the infant's attachment style as a postnatal factor. Results: Infants with secure attachment style whose mothers had experienced higher prenatal distress showed slightly better gross motor development at the age of 12 months. No association could be found between prenatal maternal distress and infant temperament. Conclusions: The results support the view that secure attachment style in children is a protective factor and softens the effects of prenatal maternal distress on difficult temperament development.

The transition to parenthood following a history of childhood maltreatment: a review of the literature on prospective and new parents' experiences

Background: Becoming a parent is viewed as one of the most important transitions in one's life. However, a history of childhood maltreatment may affect the adjustment to parenthood. Objective: The objective of this review was to synthesize the current evidence base to further our understanding of prospective and new parents' experiences in the transition to parenthood (pregnancy to 2 years post-birth), in the context of having a childhood maltreatment history. Method: A scoping review of the literature was conducted using the following online databases: PubMed, PsycINFO, PsycNET, and Published International Literature of Traumatic Stress. Results: The findings were synthesized into a four-component theoretical framework, which included mental health of the parent, physical changes, parental view of the child, and view of the self as a parent. A total of 69 papers, including 181,537 participants (of whom 30,482 mothers and 235 fathers had maltreatment histories), investigated the transition to parenthood. The majority of the studies showed that parents with a maltreatment history may suffer from a range of mental health problems during the transition to parenthood, experience more negative physical changes, and have more negative views of their child (or children). However, they reported both positive and negative experiences regarding their identity as a parent. Conclusions: The findings suggest that maltreatment is a risk factor for a more challenging transition to parenthood. Experiences of fathers with maltreatment histories merit more attention, as do those of parents in low- and middle-income countries. Future directions should include predictors of positive experiences and the development of early interventions to improve outcomes for this population.

Maternal IL-6 during pregnancy can be estimated from newborn brain connectivity and predicts future working memory in offspring

Several lines of evidence support the link between maternal inflammation during pregnancy and increased likelihood of neurodevelopmental and psychiatric disorders in offspring. This longitudinal study seeks to advance understanding regarding implications of systemic maternal inflammation during pregnancy, indexed by plasma interleukin-6 (IL-6) concentrations, for large-scale brain system development and emerging executive function skills in offspring. We assessed maternal IL-6 during pregnancy, functional magnetic resonance imaging acquired in neonates, and working memory (an important component of executive function) at 2 years of age. Functional connectivity within and between multiple neonatal brain networks can be modeled to estimate maternal IL-6 concentrations during pregnancy. Brain regions heavily weighted in these models overlap substantially with those supporting working memory in a large meta-analysis. Maternal IL-6 also directly accounts for a portion of the variance of working memory at 2 years of age. Findings highlight the association of maternal inflammation during pregnancy with the developing functional architecture of the brain and emerging executive function.

The fetal programming of telomere biology hypothesis: an update

Research on mechanisms underlying fetal programming of health and disease risk has focused primarily on processes that are specific to cell types, organs or phenotypes of interest. However, the observation that developmental conditions concomitantly influence a diverse set of phenotypes, the majority of which are implicated in age-related disorders, raises the possibility that such developmental conditions may additionally exert effects via a common underlying mechanism that involves cellular/molecular ageing-related processes. In this context, we submit that telomere biology represents a process of particular interest in humans because, firstly, this system represents among the most salient antecedent cellular phenotypes for common age-related disorders; secondly, its initial (newborn) setting appears to be particularly important for its long-term effects; and thirdly, its initial setting appears to be plastic and under developmental regulation. We propose that the effects of suboptimal intrauterine conditions on the initial setting of telomere length and telomerase expression/activity capacity may be mediated by the programming actions of stress-related maternal-placental-fetal oxidative, immune, endocrine and metabolic pathways in a manner that may ultimately accelerate cellular dysfunction, ageing and disease susceptibility over the lifespan. This perspectives paper provides an overview of each of the elements underlying this hypothesis, with an emphasis on recent developments, findings and future directions.This article is part of the theme issue 'Understanding diversity in telomere dynamics'.

The association between child exposure to intimate partner violence (IPV) and perpetration of IPV in adulthood-A systematic review

Increasingly recognized as a distinct form of childhood maltreatment, children's exposure to intimate partner violence (IPV) has been shown to be associated with an array of negative psychosocial outcomes, including elevated risk for additional violence over the life course. Although studies have identified child exposure to IPV as a predictor of IPV perpetration in adulthood, no review has critically evaluated the methodology of this quantitative work. The present study examines the association between childhood exposure to IPV and the perpetration of IPV in adulthood based on a systematic review of the literature from inception to January 4, 2016. Databases searched included Medline, Embase, PsycINFO, CINAHL, Cochrane Database of Systematic Reviews, Sociological Abstracts and ERIC. Database searches were complemented with backward and forward citation chaining. Studies were critically appraised using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Of 5601 articles identified by the search, 19 studies were included for data extraction. Sixteen of these studies found that child exposure to IPV was significantly and positively associated with adult IPV perpetration; three studies reported null findings. The methodological quality of the studies was low. Work thus far has tended to focus on child exposure to physical IPV and the perpetration of physical IPV within heterosexual contexts. In addition, measures of child exposure to IPV vary in their classification of what exposure entails. We critically discuss the strengths and limitations of the existing evidence and the theoretical frameworks informing this work.

Intergenerational Effect of Maternal Exposure to Childhood Maltreatment on Newborn Brain Anatomy

BACKGROUND

Childhood maltreatment (CM) confers deleterious long-term consequences, and growing evidence suggests some of these effects may be transmitted across generations. We examined the intergenerational effect of maternal CM exposure on child brain structure and also addressed the hypothesis that this effect may start during the child's intrauterine period of life.

METHODS

A prospective longitudinal study was conducted in a clinical convenience sample of 80 mother-child dyads. Maternal CM exposure was assessed using the Childhood Trauma Questionnaire. Structural magnetic resonance imaging was employed to characterize newborn global and regional brain (tissue) volumes near the time of birth.

RESULTS

CM exposure was reported by 35% of the women. Maternal CM exposure was associated with lower child intracranial volume (F_1,70 = 6.84, p = .011), which was primarily due to a global difference in cortical gray matter (F_1,70 = 9.10, p = .004). The effect was independent of potential confounding variables, including maternal socioeconomic status, obstetric complications, obesity, recent interpersonal violence, pre- and early postpartum stress, gestational age at birth, infant sex, and postnatal age at magnetic resonance imaging scan. The observed group difference between offspring of CM-exposed mothers versus nonexposed mothers was 6%.

CONCLUSIONS

These findings represent the first report to date associating maternal CM exposure with variation in newborn brain structure. These observations support our hypothesis of intergenerational transmission of the effects of maternal CM exposure on child brain development and suggest this effect may originate during the child's intrauterine period of life, which may have downstream neurodevelopmental consequences.

Lost connections: Oxytocin and the neural, physiological, and behavioral consequences of disrupted relationships

In humans and rodent animal models, the brain oxytocin system is paramount for facilitating social bonds, from the formation and consequences of early-life parent-infant bonds to adult pair bond relationships. In social species, oxytocin also mediates the positive effects of healthy social bonds on the partners' well-being. However, new evidence suggests that the negative consequences of early neglect or partner loss may be mediated by disruptions in the oxytocin system as well. With a focus on oxytocin and its receptor, we review studies from humans and animal models, i.e. mainly from the biparental, socially monogamous prairie vole (Microtus ochrogaster), on the beneficial effects of positive social relationships both between offspring and parents and in adult partners. The abundance of social bonds and benevolent social relationships, in general, are associated with protective effects against psycho- and physiopathology not only in the developing infant, but also during adulthood. Furthermore, we discuss the negative effects on well-being, emotionality and behavior, when these bonds are diminished in quality or are disrupted, for example through parental neglect of the young or the loss of the partner in adulthood. Strikingly, in prairie voles, oxytocinergic signaling plays an important developmental role in the ability to form bonds later in life in the face of early-life neglect, while disruption of oxytocin signaling following partner loss results in the emergence of depressive-like behavior and physiology. This review demonstrates the translational value of animal models for investigating the oxytocinergic mechanisms that underlie the detrimental effects of developmental parental neglect and pair bond disruption, encouraging future translationally relevant studies on this topic that is so central to our daily lives.

Childhood Trauma and Sleep Among Young Adults With a History of Depression: A Daily Diary Study

Child maltreatment and sleep disturbances are particularly prevalent among individuals with a history of depression. However, the precise relation between child maltreatment and sleep within this population is unclear. The present study evaluated childhood maltreatment and trauma as a predictor of sleep duration and insomnia symptoms among young adults with prior depression. A total of 102 young adults (18-22; 78% female) with a history of clinical or subclinical depression completed an in-person visit with diagnostic interviews and questionnaires of childhood trauma (maltreatment and general trauma), and 2 weeks of daily assessments of sleep and depressive symptoms using internet-capable devices. Using multilevel modeling, we found that only childhood emotional neglect significantly predicted higher levels of insomnia symptoms over the 2 weeks, controlling for daily depression. Neither childhood maltreatment nor trauma predicted sleep duration. Our findings highlight a unique relationship between emotional neglect and insomnia symptoms among individuals with a depression history that, given prior research, may potentially play a role in depression recurrence and represent a potential treatment target.

Thinking Across Generations: Unique Contributions of Maternal Early Life and Prenatal Stress to Infant Physiology

OBJECTIVE

Respiratory sinus arrhythmia (RSA) is a parasympathetic-mediated biomarker of self-regulation linked to lifespan mental and physical health outcomes. Intergenerational impacts of mothers' exposure to prenatal stress have been demonstrated, but evidence for biological embedding of maternal preconception stress, including adverse childhood experiences (ACEs), on infant RSA is lacking. We examine the independent effects of maternal ACEs and prenatal stress on infant RSA, seeking to broaden the understanding of the earliest origins of mental and physical health risk.

METHOD

Mothers reported on ACEs and prenatal stress. RSA was recorded in a sample of 167 4-month-old infants (49% female and 51% male) during a dyadic stressor, the Still Face Paradigm.

RESULTS

Independent contributions of maternal ACEs and prenatal stress to infant RSA were observed. High maternal ACEs were associated with lower RSA, whereas prenatal stress was associated with failure to recover following the stressor. Sex but not race differences were observed. Prenatal stress was associated with higher RSA among boys but lower RSA among girls.

CONCLUSION

Infants' RSA is affected by mothers' life course experiences of stress, with ACEs predicting a lower set point and prenatal stress dampening recovery from stress. For prenatal stress but not ACEs, patterns vary across sex. Findings underscore that stress-reducing interventions for pregnant women or those considering pregnancy may lead to decreased physical and mental health risk across generations.