Prenatal maternal stress and offspring aggressive behavior: Intergenerational and transgenerational inheritance

Even though studies have shown that prenatal maternal stress is associated with increased reactivity of the HPA axis, the association between prenatal maternal stress and fetal glucocorticoid exposure is complex and most likely dependent on unidentified and poorly understood variables including nature and timing of prenatal insults. The precise mechanisms in which prenatal maternal stress influence neuroendocrine signaling between the maternal-placental-fetal interface are still unclear. The aim of this review article is to bring comprehensive basic concepts about prenatal maternal stress and mechanisms of transmission of maternal stress to the fetus. This review covers recent studies showing associations between maternal stress and alterations in offspring aggressive behavior, as well as the possible pathways for the “transmission” of maternal stress to the fetus: (1) maternal-fetal HPA axis dysregulation; (2) intrauterine environment disruption due to variations in uterine artery flow; (3) epigenetic modifications of genes implicated in aggressive behavior. Here, we present evidence for the phenomenon of intergenerational and transgenerational transmission, to better understands the mechanism(s) of transmission from parent to offspring. We discuss studies showing associations between maternal stress and alterations in offspring taking note of neuroendocrine, brain architecture and epigenetic changes that may suggest risk for aggressive behavior. We highlight animal and human studies that focus on intergenerational transmission following exposure to stress from a biological mechanistic point of view, and maternal stress-induced epigenetic modifications that have potential to impact on aggressive behavior in later generations.

Exploring sex differences in fetal programming for childhood emotional disorders

In examining maternal depression, placental 11β-HSD2 mRNA expression and offspring cortisol regulation as a potential fetal programming pathway in relation to later child emotional disorders, it has become clear that sex differences may be important to consider. This study reports on data obtained from 209 participants in the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS) recruited before 20 weeks of pregnancy. Maternal depressive disorders were diagnosed using the SCID-IV and maternal childhood trauma using the Childhood Trauma Questionnaire. Placental 11β-HSD2 mRNA was measured using qRT-PCR. For assessment of stress-induced cortisol reactivity, salivary cortisol samples were taken at 12 months of age. At 4 years of age, measurement of Childhood Emotional Disorders (depression and anxiety) was based on maternal report using the Preschool Age Psychiatric Assessment (PAPA) and internalizing symptoms using the Child Behavior Checklist (CBCL). Maternal depression in pregnancy and postpartum, and infant cortisol reactivity, was associated with internalizing symptoms for females only. For female offspring only, increased 12-month cortisol reactivity was also associated with increased emotional disorders at 4 years of age; however, there was no association with placental 11β-HSD2 mRNA expression. In females only, the combination of lower placental 11β-HSD2 mRNA expression and higher cortisol reactivity at 12 months of age predicted increased internalising problems. These findings suggest there may be sex differences in prenatal predictors and pathways for early childhood depression and anxiety symptoms and disorder.

Maternal and paternal depression and child mental health trajectories: evidence from the Avon Longitudinal Study of Parents and Children

BACKGROUND

The relationships between offspring depression profiles across adolescence and different timings of parental depression during the perinatal period remain unknown.

AIMS

To explore different timings of maternal and paternal perinatal depression in relation to patterns of change in offspring depressive mood over a 14 year period.

METHOD

Data were obtained from the Avon Longitudinal Study of Parents and Children (ALSPAC). Parental antenatal depression (ANTD) was assessed at 18 weeks gestation, and postnatal depression (PNTD) at 8 weeks postpartum. Population-averaged trajectories of offspring depressive symptoms were estimated using the Short Mood and Feelings Questionnaire (SMFQ) on nine occasions between 10 and 24 years of age.

RESULTS

Full data were available for 5029 individuals. Offspring exposed to both timings of maternal depression had higher depressive symptoms across adolescence compared with offspring not exposed to ANTD or PNTD, characterised by higher depressive symptoms at age 16 (7.07 SMFQ points (95% CI = 6.19, 7.95; P < 0.001)) and a greater rate of linear change (0.698 SMFQ points (95% CI = 0.47, 0.93; P = 0.002)). Isolated maternal ANTD and to a lesser extent PNTD were also both associated with higher depressive symptoms at age 16, yet isolated maternal PNTD showed greater evidence for an increased rate of linear change across adolescence. A similar pattern was observed for paternal ANTD and PNTD, although effect sizes were attenuated.

CONCLUSIONS

This study adds to the literature demonstrating that exposure to two timings of maternal depression (ANTD and PNTD) is strongly associated with greater offspring trajectories of depressive symptoms.

HPA-axis multilocus genetic profile score moderates the association between maternal prenatal perceived stress and offspring depression in early adulthood

Maternal stress during pregnancy can cause alterations to the fetal hypothalamus-pituitary-adrenal (HPA) axis, a phenomenon known as fetal programming that may have lasting effects on offspring outcomes, including depression. Evidence suggests that these effects may vary with respect to the offspring's genetic risk. Nonetheless, few studies have examined these effects into adulthood, when risk for depression onset is highest. The present study builds upon the extant literature by examining the interaction of maternal prenatal perceived stress (MPPS) and offspring HPA-axis polygenic risk to predict offspring depression in early adulthood. A total of 381 mother-child dyads participated in a prospective, longitudinal study that spanned from pregnancy until offspring were 20 years of age. Polygenic risk was defined by a multilocus genetic profile score (MGPS) that reflected the additive risk of three HPA-axis candidate genes. The results indicated that the interaction of MPPS and HPA-axis MGPS confers risk for offspring depression at age 20, in line with the differential susceptibility model. This interaction may be specific to prenatal stress, as maternal stress during early childhood did not interact with genetic risk to predict depression. These findings provide the first evidence that genetic variants that are associated with the HPA axis may act in a polygenic, additive fashion to moderate the association between fetal programming and adult depression.

Prenatal stress, health, and health behaviours during the COVID-19 pandemic: An international survey

Background

Pregnant women’s stress, mental and physical health, and health behaviours can have important implications for maternal and child health outcomes.

Aim

To examine pregnant women’s levels of stress, mental and physical health, and health behaviours during the COVID-19 pandemic.

Methods

A cross-sectional survey was conducted online, with recruitment and data collection occurring between 16/6/20 and 17/7/20. Participants were pregnant women recruited via online pregnancy/parenting communities. Participants self-reported their levels of general stress, pregnancy-specific stress and COVID-19 related stress, mental and physical health, general health behaviours, and COVID-19 related health behaviours.

Findings

573 pregnant women participated in the survey. Participants were most commonly resident in the United States (42.6%, n = 243), Ireland (41.2%, n = 235) or the United Kingdom (10%, n = 57). The majority (80.0%, n = 457) were married and educated to degree level or above (79.3, n = 453). Pregnant women reported high levels of pregnancy-specific and COVID-19-related stress, and low levels of mental and physical health, during the pandemic. Encouragingly, pregnant women in this study generally reported high levels of adherence to public health advice and pregnancy health behaviours. Stress and general mental health outcomes were best predicted by well-being factors (including stress and social support). Health impairing behaviours (e.g. poor diet) were predicted by both well-being and demographic factors.

Discussion

Interventions targeting pregnancy- and pandemic-specific stress at the population level will be essential to support mental health and minimise adverse outcomes for women and children during the pandemic.

Human attachment triggers different social buffering mechanisms under high and low early life stress rearing

Social buffering - the attenuation of stress by maternal safety signals - is a core mammalian-general stress management mechanism implicating two ancient systems: the oxytocinergic and HPA systems. Yet, because human attachments are representation-based, understanding social buffering mechanisms in humans requires the assessment of relationship history and consideration of early life stress (ELS), which alters stress responsivity. We followed a unique trauma-exposed cohort across childhood, versus a low-stress control group, and repeatedly observed maternal sensitive, safety-promoting style. In adolescence, we used an attachment induction paradigm that exposed children to both live and reminders of attachment safety signals and measured oxytocin and cortisol baseline and response, to test how maternal safety signals impact hormonal reactivity in children reared under high- versus low-stress conditions. Only safety-promoting mothers exhibited a stress-buffering function, but their effect was system-specific and depended on the rearing context. For oxytocin, safety-promoting mothers normalized the deficient baseline oxytocin levels observed in ELS youth by implicating a plasticity-by-affiliation mechanism. For cortisol, safety-promoting mothering reduced the initial stress response only among youth reared in low-stress contexts via the typical buffering-by-safety mechanism. Results suggest that human attachments require internalized security evolving over time to trigger a stress buffering function. Under conditions of chronic early stress, the stressful rearing context overrides the maternal safety signals, normative stress buffering mechanisms fail, and safety-promoting mothers switch to an immature, affiliation-based mechanism that relies on maternal presence.

Maternal antenatal anxiety and electrophysiological functioning amongst a sub-set of preschoolers participating in the GUSTO cohort

BACKGROUND

Antenatal maternal anxiety is a risk for offspring psychological and cognitive difficulties. The preschool years represent an important time for brain development, and so may be a window for intervention. However, electrophysiological investigations of maternal anxiety and preschoolers' brain functioning are lacking. We ask whether anxiety symptoms predict neurophysiology, and consider timing specificity (26-weeks antenatal or 24-months postnatal), form of insult (anxiety symptoms, per se, or also depression symptoms), and offspring gender.

METHODS

The sample consisted of a subset of 71 mothers and their 3 year old children taking part in the prospective birth cohort, GUSTO. Mothers provided antenatal (26 weeks) and postnatal (2 years) anxiety and depressive symptomatology data, respectively via the "State Trait Anxiety Questionnaire" and the "Edinburgh Postpartum Depression Scale." Offspring provided electrophysiological data, obtained while they indicated the emotional expression of actors whose facial expressions remained consistent throughout a pre-switch block, but were reversed at "post-switch."

RESULTS

Three electrophysiological components linked to different information processing stages were identified. The two earliest occurring components (i.e., the N1 and P2) differed across blocks. During post-switch, both were significantly predicted by maternal anxiety, after controlling for pre-switch neurophysiology. Similar results were observed with depression. Antenatal mental health remained a significant predictor after controlling for postnatal mental health.

CONCLUSION

In combination with past work, these findings suggest the importance of reducing symptoms in women prior to and during pregnancy, and offering support to offspring early in development.

Does Prenatal Maternal Distress Contribute to Sex Differences in Child Psychopathology?

PURPOSE OF REVIEW

Prenatal maternal psychological distress is an established risk factor for the development of psychopathology in offspring. The purpose of this review is to evaluate whether sex differences in fetal responses to maternal distress contribute to sex differences in subsequent psychopathology.

RECENT FINDINGS

Male and female fetuses respond differently to stress signals. We review recent evidence that demonstrates a sex-specific pattern of association between prenatal maternal distress and pathways associated with risk for psychopathology including offspring hypothalamic pituitary adrenocortical (HPA) axis regulation, brain development, and negative emotionality. Prenatal maternal distress exerts sex-specific consequences on the fetus. These differences may contribute to the well-established sex differences in psychopathology and in particular to greater female vulnerability to develop internalizing problems.

Prenatal depression, fetal neurobehavior, and infant temperament: Novel insights on early neurodevelopment from a socioeconomically disadvantaged Indian cohort

This article extends the research focusing on the early origins of psychopathology into the prenatal period, by exploring the association between maternal prenatal depression and offspring (fetal and infant) neurobehavior. The sample is recruited from a rural population in South India where women in the third trimester of pregnancy were assessed for depression and the heart rate responses of their fetuses to extrinsically applied vibroacoustic stimuli were studied. At 2 months postbirth, infant temperament and cortisol responsivity to immunization were assessed. The association between maternal prenatal depression and fetal responsivity to vibroacoustic stimulation, and infant responsivity to immunization, was U shaped with higher levels of responsivity noted in the offspring of mothers with very high and very low depression scores, and lower levels noted in the offspring of mothers with moderate depression scores. Maternal prenatal depression was not associated with infant temperament. The findings highlight the importance of environmental influences in the developmental origins of neurobehavior, suggesting that such differences, not evident at baseline, may emerge upon exposure to stressors. The study also emphasizes the need for further investigation in low- and middle-income contexts by providing preliminary evidence of the differing patterns of association observed between high- and low-income populations.

Risks of using SSRI / SNRI antidepressants during pregnancy and lactation

At present, affective disorders are among the most commonly diagnosed mental diseases. In pregnancy, they can occur as pre-delivery depression, recurrent depressive disorder or postnatal depression. The estimated prevalence of depressive disorders in pregnancy is approximately 9–16%, with some statistics reporting up to 20%. Approximately 2–3% of pregnant women take antidepressants during pregnancy, and the number of mothers treated increases by birth to 5–7%. Treatment of depression during pregnancy and breastfeeding is a controversial issue, as antidepressants can negatively affect the developing fetus. According to epidemiological studies, the effects of treated depression in pregnancy are related to premature birth, decreased body weight of the child, intrauterine growth retardation, neonatal adaptive syndrome, and persistent pulmonary hypertension. However, untreated depression can adversely affect maternal health and increase the risk of preeclampsia and eclampsia, as well as of subsequent postnatal depression, which can lead to disruption of the mother-child relationship. Based on the above mentioned facts, the basic question arises as to whether or not to treat depression during pregnancy and lactation.

The impact of psychological distress during pregnancy on the developing fetus: biological mechanisms and the potential benefits of mindfulness interventions

The in utero environment plays an essential role in shaping future growth and development. Psychological distress during pregnancy has been shown to perturb the delicate physiological milieu of pregnancy, and has been associated with negative repercussions in the offspring, including adverse birth outcomes, long-term defects in cognitive development, behavioral problems during childhood and high baseline levels of stress-related hormones. Fetal epigenetic programming, involving epigenetic processes, may help explain the link between maternal prenatal stress and its negative effects on the child. Given the potential long-term effects of early-life stress on a child's health, it is crucial to minimize maternal distress during pregnancy. A number of recent studies have examined the usefulness of mindfulness-based programs to reduce prenatal psychological stress and improve maternal psychological health, and these are reviewed here. Overall, the findings are promising, but more research is needed with large studies using randomized controlled study designs. It remains unclear whether or not such interventions could also improve child health outcomes, and whether these changes are modulated at the epigenetic level during fetal development. Further studies in this area are needed.

Maternal Prenatal Psychological Distress and Preschool Cognitive Functioning: the Protective Role of Positive Parental Engagement

Considerable animal research and available human studies suggest that psychological distress experienced by mothers during gestation is associated with later neurodevelopmental deficits in offspring; however, little research has examined potential protective factors that might mitigate this risk. The current study examined the impact of maternal prenatal psychological distress during pregnancy on cognitive outcomes in preschoolers (ages 2.5-5 years) and positive parenting as a potential protective factor. Mother-child dyads (N = 162, mean child age = 44 months, 49 % female) were recruited from a longitudinal cohort of women who had previously participated in a study of maternal mood disorders during pregnancy. Maternal prenatal distress was assessed with multiple measures collected throughout pregnancy. During a follow-up visit, mothers were interviewed about their psychological symptoms since the birth of the child, parenting behaviors were recorded during a parent-child interaction, and children's cognitive abilities were measured using the Differential Ability Scales, 2nd Edition. Maternal prenatal distress significantly predicted lower general cognitive abilities; however, this relationship was strongest for children whose mothers exhibited low levels of positive engagement and not significant when mothers exhibited high levels of positive engagement. Results suggest that positive parental engagement can protect against the detrimental effects of maternal prenatal distress on preschoolers' cognitive abilities.

Developmental origins of the human hypothalamic-pituitary-adrenal axis

INTRODUCTION

The developmental origins of disease or fetal programming model predicts that intrauterine exposures have life long consequences for physical and psychological health. Prenatal programming of the fetal hypothalamic-pituitary-adrenal (HPA) axis is proposed as a primary mechanism by which early experiences are linked to later disease risk. Areas covered: This review describes the development of the fetal HPA axis, which is determined by an intricately timed cascade of endocrine events during gestation and is regulated by an integrated maternal-placental-fetal steroidogenic unit. Mechanisms by which stress-induced elevations in hormones of maternal, fetal, or placental origin influence the structure and function of the emerging fetal HPA axis are discussed. Recent prospective studies documenting persisting associations between prenatal stress exposures and altered postnatal HPA axis function are summarized, with effects observed beginning in infancy into adulthood. Expert commentary: The results of these studies are synthesized, and potential moderating factors are discussed. Promising areas of further research highlighted include epigenetic mechanisms and interactions between pre and postnatal influences.

MATERNAL INTERACTION QUALITY MODERATES EFFECTS OF PRENATAL MATERNAL EMOTIONAL SYMPTOMS ON GIRLS' INTERNALIZING PROBLEMS

The role of mother-infant interaction quality is studied in the relation between prenatal maternal emotional symptoms and child behavioral problems. Healthy pregnant, Dutch women (N = 96, M = 31.6, SD = 3.3) were allocated to the "exposed group" (n = 46), consisting of mothers with high levels of prenatal feelings of anxiety and depression, or the "low-exposed group" (n = 50), consisting of mothers with normal levels of depressive or anxious symptoms during pregnancy. When the children (49 girls, 47 boys) were 23 to 60 months of age (M = 39.0, SD = 9.6), parents completed the Child Behavior Checklist (T.M. Achenbach & L.A. Rescorla, ), and mother-child interaction quality during a home visit was rated using the Emotional Availability Scales. There were no differences in mother-child interaction quality between the prenatally exposed and low-exposed groups. Girls exposed to high prenatal emotional symptoms showed more internalizing problems, if maternal interaction quality was less optimal. No significant effects were found for boys.

Maternal prenatal cortisol predicts infant negative emotionality in a sex-dependent manner

OBJECTIVE

Prenatal stress influences fetal developmental trajectories, which may implicate glucocorticoid mechanisms. There is also emerging evidence that effects of prenatal stress on offspring development are sex-dependent. However, little is known about the prospective relationship between maternal prenatal cortisol levels and infant behaviour, and whether it may be different in male and female infants. We sought to address this question using data from a prospective longitudinal cohort, stratified by risk.

METHOD

The Wirral Child Health and Development Study (WCHADS) cohort (n=1233) included a stratified random sub-sample (n=216) who provided maternal saliva samples, assayed for cortisol, at home over two days at 32weeks of pregnancy (on waking, 30-min post-waking and during the evening) and a measure of infant negative emotionality from the Neonatal Behavioural Assessment Scale (NBAS) at five weeks-of-age. General population estimates of associations among measures were obtained using inverse probability weights.

RESULTS

Maternal prenatal cortisol sampled on waking predicted infant negative emotionality in a sex-dependent manner (interaction term, p=0.005); female infants exposed to high levels of prenatal cortisol were more negative (Beta=0.440, p=0.042), whereas male infants were less negative (Beta=-0.407, p=0.045). There was no effect of the 30-min post-waking measure or evening cortisol.

DISCUSSION

Our findings add to an emerging body of work that has highlighted sex differences in fetal programming, whereby females become more reactive following prenatal stress, and males less reactive. A more complete understanding of sex-specific developmental trajectories in the context of prenatal stress is essential for the development of targeted prevention strategies.

Sex differences in early-life programming of the hypothalamic-pituitary-adrenal axis in humans suggest increased vulnerability in females: a systematic review

Fetal glucocorticoid overexposure is a key mechanism linking early development with later-life disease. In humans, low birth weight associates with increased fasting cortisol, hypothalamic-pituitary-adrenal (HPA) axis reactivity, and with cardiovascular risk and cognitive decline. As there are sex differences in these adult diseases, we hypothesized that there may be sex differences in programming of the HPA axis in response to prenatal stressors. We conducted a systematic review following Meta-Analysis of Observational Studies in Epidemiology and Preferred Reporting Items for Systematic Reviews and Meta-Analysis. We searched Embase, MEDLINE and Web of Science from inception to 31 October 2016. We included studies related to sex differences, prenatal exposures and HPA axis. We excluded studies investigating specific disease states. The 23 included studies investigated the consequences of low birth weight, preterm birth and maternal stressors of asthma, psychosocial stress and glucocorticoid medications on HPA axis outcomes of placental glucocorticoid biology and offspring HPA axis function in early life and later life. Female offspring exposed to stressors had increased HPA axis reactivity compared with males. Furthermore, the female placenta increased its permeability to maternal glucocorticoids following maternal stress with changes in the expression of 11β-hydroxysteroid dehydrogenase enzymes in response to maternal glucocorticoid exposure or asthma. Among males there was some evidence of altered diurnal cortisol secretion. We conclude that although there is some evidence of male vulnerability leading to altered diurnal cortisol secretion, the female HPA axis is more vulnerable to programming, particularly in terms of its reactivity; this suggests a mechanism underlying sex differences in later-life diseases.

Maternal depression across the first years of life compromises child psychosocial adjustment; relations to child HPA-axis functioning

Maternal depression across the first years of life negatively impacts children's development. One pathway of vulnerability may involve functioning of the hypothalamic-pituitary-adrenal (HPA) axis. We utilize a community cohort of 1983 women with no comorbid risk repeatedly assessed for depression from birth to six years to form two groups; chronically depressed (N=40) and non-depressed (N=91) women. At six years, mother and child underwent psychiatric diagnosis, child salivary cortisol (CT) was assessed three times during a home-visit, mother-child interaction was videotaped, and child empathy was coded from behavioral paradigms. Latent Growth curve Model using Structural Equation Modeling (SEM) estimated the links between maternal depression and mother's negative parenting and three child outcomes; psychopathology, social withdrawal, and empathy as related to child CT baseline and variability. Depressed mothers displayed more negative parenting and their children showed more Axis-I psychopathology and social withdrawal. SEM analysis revealed that maternal depression was associated with reduced CT variability, which predicted higher child psychopathology and social withdrawal. Whereas all children exhibited similar initial levels of CT, children of controls reduced CT levels over time while children of depressed mothers maintained high, non-flexible levels. Mother negativity was related to lower initial CT levels, which predicted decreased empathy. Findings suggest that chronic maternal depression may compromise children's social-emotional adjustment by diminishing HPA-system flexibility as well as limiting the mother's capacity to provide attuned and predictable caregiving.

Effects of Maternal Cortisol during Pregnancy on Children's Blood Pressure Responses

BACKGROUND

It is well established that birth weight has an effect on subsequent blood pressure. Predominantly experimental studies have also reported effects of altered corticosteroid levels on subsequent cardiovascular responses. In the current study, we have examined the effects of both birth weight and maternal cortisol levels in a cohort of mothers and their pre-adolescent children.

PROCEDURE

A total of 216 women and their 7- to 9-year-old children comprised the cohort. The women had been assessed for plasma cortisol during the first (n = 71), second (n = 72) and third (n = 73) trimester. Maternal cortisol had been measured on a fasting sample taken between 9 and 11 a.m. The children's blood pressure and heart rate were recorded in the resting state, in response to a 10-min video game stress challenge and during recovery. Resting values, incremental responses to stress and recovery were evaluated.

OBSERVATION

Maternal cortisol levels increased with duration of pregnancy. There were inverse correlations between birth weight and all haemodynamic measures. The positive associations between maternal cortisol and children's haemodynamic measures were most evident in the first and second trimesters. Birth weight was inversely related to maternal cortisol. In multiple regression analyses, the effects of maternal cortisol were more consistent than those of birth weight.

CONCLUSION

Both birth weight and maternal cortisol are predictive of children's resting and stress-modulated haemodynamic measures. The effects of birth weight may partly mediate the effects of maternal cortisol.

Are female children more vulnerable to the long-term effects of maternal depression during pregnancy?

BACKGROUND

Female fetuses are more vulnerable to high levels of maternal glucocorticoids. We examined whether exposure to prenatal maternal depression, a condition associated with high glucocorticoids, carries greater risk for depression at 12 and 18 years in girls.

METHODS

Our sample comprised 7959 mothers and children from the Avon Longitudinal Study of Parents and Children following imputation for missing data. Maternal depression was assessed pre-and post-natally, and offspring depression at ages 12 and 18. We used logistic regression models to examine the relationship between exposure to prenatal and postnatal depression and offspring depression at 18 and 12 and interactions with gender.

RESULTS

There was an interaction between prenatal depression and gender (P=0.027) and between postnatal depression and gender (P=0.027) for offspring depression at 18. Following adjustment in pre-natally depressed mothers, the odds ratio for offspring depression at 18 was 1.55 (95% c.i. 1.03-2.34) for girls and 0.54 (0.23-1.26) for boys. In post-natally depressed mothers, the odds ratio for offspring depression at 18 was 1.15 (0.70-1.89) in girls and 3.13 (1.52-6.45) in boys. However there was no evidence for interaction between prenatal or postnatal depression and gender (P=0.559 and 0.780 respectively) for offspring depression at 12.

LIMITATIONS

As expected with this large cohort spanning over 18 years, there was loss-to-follow-up.

CONCLUSIONS

This is the first evidence in humans that increased vulnerability of female fetuses to maternal stress responses during pregnancy persists into adolescence. One explanation for gender differences emerging later is more depressive symptomatology is attributed to heritable risk at 12, whereas biological processes involved in brain development at 18 may be influenced by foetal programming. If replicated, this study has potential to help understand intergenerational transmission of depression, a leading cause of morbidity worldwide.

Depression symptoms during pregnancy: Evidence from Growing Up in New Zealand

BACKGROUND

Depression during pregnancy has significant implications for pregnancy outcomes and maternal and child health. There is a need to identify which family, physical and mental health factors are associated with depression during pregnancy.

METHODS

An ethnically and socioeconomically diverse sample of 5664 pregnant women living in New Zealand completed a face-to-face interview during the third trimester. Antenatal depression (AD) symptoms were assessed using the Edinburgh Postnatal Depression Scale (EPDS). Maternal demographic, physical and mental health, and family and relationship characteristics were measured. The association between symptoms of AD and maternal characteristics was determined using multiple logistic regression.

RESULTS

11.9% of the participating women had EPDS scores (13+) that indicated probable AD. When considering sociodemographic predictors of AD symptoms, we found that women from non-European ethnicities, specifically Pacific Islander, Asian and other, were more likely to suffer from AD symptoms. Greater perceived stress during pregnancy and a diagnosis of anxiety both before and during pregnancy were also associated with greater odds of having AD according to the EPDS.

LIMITATIONS

The women were in their third trimester of pregnancy at the interview. Therefore, we cannot discount the possibility of recall bias for questions relating to pre-pregnancy status or early-pregnancy behaviours.

CONCLUSIONS

AD is prevalent amongst New Zealand women. Ethnicity, perceived stress and anxiety are particularly associated with a greater likelihood of depression during pregnancy. Further attention to supporting maternal mental health status in the antenatal period is required.

Foetal exposure to maternal depression predicts cortisol responses in infants: findings from rural South India

BACKGROUND

Maternal depression during pregnancy is associated with an increased risk of adverse child outcomes. One potential mechanism is the influence of antenatal depression on the foetal hypothalamic-pituitary-adrenal axis. This can be observed as disturbances in baseline cortisol secretion during childhood. The influence of antenatal depression on infant cortisol reactivity to a stressor may provide further insight into this association. In addition, the dose-response relationship between foetal exposure to antenatal depression and infant cortisol reactivity is unclear.

METHODS

A consecutive sample of 133 pregnant women in their third trimester was recruited from an antenatal clinic in Karnataka, South India. Women were assessed for depression before and after birth on the Edinburgh Postnatal Depression Scale (EPDS) and the Kessler 10 Scale. Salivary cortisol response to immunization was measured in 58 infants at 2 months of age. We aimed (i) to investigate the association between antenatal depression and infant cortisol reactivity to immunization and (ii) to explore whether the relationship is dose-dependent.

RESULTS

Exposure to antenatal depression independently predicted elevated infant cortisol responses to immunization (β = 0.53, P = 0.04). The association was found to be U-shaped, for antenatal depression measured on the EPDS, with the infants exposed to the highest and lowest levels of maternal antenatal EPDS scores during intra-uterine life showing elevated cortisol responses to immunization (R(2) = 0.20, P = 0.02). Infants exposed to moderate levels of maternal antenatal depression showed the lowest cortisol response to immunization.

CONCLUSIONS

These findings suggest that the association between antenatal depression and infant cortisol reactivity is dose-dependent and U-shaped, implying that infants exposed to both low and high levels of maternal depression showed greater reactivity. The study provides the first evidence of such an association from a low-income setting.

The gestational foundation of sex differences in development and vulnerability

Despite long-standing interest in the role of sex on human development, the functional consequences of fetal sex on early development are not well-understood. Here we explore the gestational origins of sex as a moderator of development. In accordance with the focus of this special issue, we examine evidence for a sex differential in vulnerability to prenatal and perinatal risks. Exposures evaluated include those present in the external environment (e.g., lead, pesticides), those introduced by maternal behaviors (e.g., alcohol, opioid use), and those resulting from an adverse intrauterine environment (e.g., preterm birth). We also provide current knowledge on the degree to which sex differences in fetal neurobehavioral development (i.e., cardiac and motor patterns) are present prior to birth. Also considered are contemporaneous and persistent sex of fetus effects on the pregnant woman. Converging evidence confirms that infant and early childhood developmental outcomes of male fetuses exposed to prenatal and perinatal adversities are more highly impaired than those of female fetuses. In certain circumstances, male fetuses are both more frequently exposed to early adversities and more affected by them when exposed than are female fetuses. The mechanisms through which biological sex imparts vulnerability or protection on the developing nervous system are largely unknown. We consider models that implicate variation in maturation, placental functioning, and the neuroendocrine milieu as potential contributors. Many studies use sex as a control variable, some analyze and report main effects for sex, but those that report interaction terms for sex are scarce. As a result, the true scope of sex differences in vulnerability is unknown.

Mechanisms and correlates of a healthy brain: a commentary

In this monograph, the message is that early inactivity and obesity lead to later chronic disease, and, as such, physical inactivity should be recognized as a public health crisis. Sedentary behavior, to some extent, serves a purpose in our current culture (e.g., keeping children indoors keeps them safe), and, as such, may not be amenable to change. Thus, it is important that we understand the underpinnings of later-developing chronic disease as this complex public health issue may have roots that go deeper than sedentary behavior. In this commentary, I speculate on the mechanisms for physical activity exacting positive changes on cognitive abilities. Three potential mechanisms are discussed: glucose transport, postnatal neurogenesis, and vitamin synthesis, all of which are inextricably linked to nutrition. This discussion of mechanisms is followed by a discussion of tractable correlates of the progression to non-communicable disease in the adult.

Influence of sex and stress exposure across the lifespan on endophenotypes of depression: focus on behavior, glucocorticoids, and hippocampus

Sex differences exist in vulnerability, symptoms, and treatment of many neuropsychiatric disorders. In this review, we discuss both preclinical and clinical research that investigates how sex influences depression endophenotypes at the behavioral, neuroendocrine, and neural levels across the lifespan. Chronic exposure to stress is a risk factor for depression and we discuss how stress during the prenatal, postnatal, and adolescent periods differentially affects males and females depending on the method of stress and metric examined. Given that the integrity of the hippocampus is compromised in depression, we specifically focus on sex differences in how hippocampal plasticity is affected by stress and depression across the lifespan. In addition, we examine how female physiology predisposes depression in adulthood, specifically in postpartum and perimenopausal periods. Finally, we discuss the underrepresentation of women in both preclinical and clinical research and how this limits our understanding of sex differences in vulnerability, presentation, and treatment of depression.

Peripartum depression and anxiety as an integrative cross domain target for psychiatric preventative measures

Exposure to high levels of early life stress has been identified as a potent risk factor for neurodevelopmental delays in infants, behavioral problems and autism in children, but also for several psychiatric illnesses in adulthood, such as depression, anxiety, autism, and posttraumatic stress disorder. Despite having robust adverse effects on both mother and infant, the pathophysiology of peripartum depression and anxiety are poorly understood. The objective of this review is to highlight the advantages of using an integrated approach addressing several behavioral domains in both animal and clinical studies of peripartum depression and anxiety. It is postulated that a greater focus on integrated cross domain studies will lead to advances in treatments and preventative measures for several disorders associated with peripartum depression and anxiety.

Sexually dimorphic responses to early adversity: implications for affective problems and autism spectrum disorder

During gestation, development proceeds at a pace that is unmatched by any other stage of the life cycle. For these reasons the human fetus is particularly susceptible not only to organizing influences, but also to pathogenic disorganizing influences. Growing evidence suggests that exposure to prenatal adversity leads to neurological changes that underlie lifetime risks for mental illness. Beginning early in gestation, males and females show differential developmental trajectories and responses to stress. It is likely that sex-dependent organization of neural circuits during the fetal period influences differential vulnerability to mental health problems. We consider in this review evidence that sexually dimorphic responses to early life stress are linked to two developmental disorders: affective problems (greater female prevalence) and autism spectrum disorder (greater male prevalence). Recent prospective studies illustrating the neurodevelopmental consequences of fetal exposure to stress and stress hormones for males and females are considered here. Plausible biological mechanisms including the role of the sexually differentiated placenta are discussed.

Early origins of health disparities: material deprivation predicts maternal evening cortisol in pregnancy and offspring cortisol reactivity in the first few weeks of life

OBJECTIVES

Maternal hypothalamic pituitary adrenal-axis function regulates production of the stress hormone cortisol, which during pregnancy can cross the placenta and have lasting impacts on fetal growth and development. This article provides a preliminary test of the hypothesis that a woman's socioeconomic status (SES) predicts her cortisol during pregnancy and her offspring's cortisol during the early postnatal period among an ethnically diverse sample in Auckland, New Zealand to evaluate whether differences in cortisol contribute to the intergenerational inheritance of health disparities within this population.

METHODS

Maternal saliva samples were collected at waking and prior to sleep on 2 days in late pregnancy (34-36 weeks gestation; N = 55), and a subset of offspring saliva was collected before (N = 48) and 20 min after a standard vaccination at 6 weeks of age (N = 19). SES was quantified using a locally validated index of material deprivation, the NZ Deprivation Index for individuals (NZiDep).

RESULTS

We found that, after controlling for ethnicity and other covariates, women with higher NZiDep scores had significantly higher evening but similar morning cortisol, consistent with a pattern of chronic strain. Infants of women reporting greater material deprivation had elevated cortisol response to vaccination.

CONCLUSIONS

These findings suggest that maternal SES experience impacts maternal cortisol in pregnancy and offspring cortisol reactivity soon after birth, with potential long-term effects on offspring biology and health. Additional research is needed to clarify how biological and behavioral factors in both the prenatal and postnatal period facilitate this relationship.

Impact of maternal prenatal stress on growth of the offspring

Unperturbed fetal development is essential for future health of an individual. Previous studies have linked diseases of aging to harmful alterations that happen during fetal development. Given the significant long-term impact that intrauterine environment has on an individual's life, it was hypothesized that maternal stress during pregnancy will have negative effects on the offspring's prenatal and postnatal growth. To test this, twenty-eight female and seven male Wistar rats (Rattus norvegicus) were purchased and bred to produce 176 offspring. During pregnancy, dams were randomly divided into four groups (n=7, per group) and immobilization stress induced as follows; Group 1 (GW1): immobilization stress on days 1-7 of pregnancy, Group 2 (GW2): on days 8-14, Group 3 (GW3): on days 15-21, Group 4 (Controls): left undisturbed. Maternal cortisol hormone, food intake, and weight gain were monitored during pregnancy. Pups were raised under normal laboratory conditions and sacrificed at ages: 4, 8, 12, and 16 weeks to determine the effect of prenatal stress. At necropsy, the tibia was removed and processed for histology. Differences among groups were determined by T-test or analysis of variance (ANOVA). Linear regression analysis was performed to establish the relationship between stress in utero and indicators of bone development in offspring. P values ≤ 0.05 were considered significant. Cortisol hormone levels in controls were lower than those of stressed animals. Stressed dams consumed 12.5% less food per day compared to controls. Animals in GW1 and GW2 gained less weight during pregnancy but had larger litters than did GW3 or the control group. Offspring born to GW3 were heavier compared to all other groups. GW3 offspring had a higher rate of bone formation. In conclusion, stress during pregnancy resulted in increased cortisol and reduced food intake in mothers, but faster growth and higher weight gain in offspring compared to controls.

The social brain: neurobiological basis of affiliative behaviours and psychological well-being

The social brain hypothesis proposes that the demands of the social environment provided the evolutionary pressure that led to the expansion of the primate brain. Consistent with this notion, that functioning in the social world is crucial to our survival, while close supportive relationships are known to enhance well-being, a range of social stressors such as abuse, discrimination and dysfunctional relationships can increase the risk of psychiatric disorders. The centrality of the social world to our everyday lives is further exemplified by the fact that abnormality in social behaviour is a salient feature of a range of neurodevelopmental and psychiatric disorders. This paper aims to provide a selective overview of current knowledge of the neurobiological basis of our ability to form and maintain close personal relationships, and of the benefits these relationships confer on our health. Focusing on neurochemical and neuroendocrine interactions within affective and motivational neural circuits, it highlights the specific importance of cutaneous somatosensation in affiliative behaviours and psychological well-being and reviews evidence, in support of the hypothesis, that a class of cutaneous unmyelinated, low threshold mechanosensitive nerves, named c-tactile afferents, have a direct and specific role in processing affiliative tactile stimuli.

Frequency of infant stroking reported by mothers moderates the effect of prenatal depression on infant behavioural and physiological outcomes

Animal studies find that prenatal stress is associated with increased physiological and emotional reactivity later in life, mediated via fetal programming of the HPA axis through decreased glucocorticoid receptor (GR) gene expression. Post-natal behaviours, notably licking and grooming in rats, cause decreased behavioural indices of fear and reduced HPA axis reactivity mediated via increased GR gene expression. Post-natal maternal behaviours may therefore be expected to modify prenatal effects, but this has not previously been examined in humans. We examined whether, according to self-report, maternal stroking over the first weeks of life modified associations between prenatal depression and physiological and behavioral outcomes in infancy, hence mimicking effects of rodent licking and grooming. From a general population sample of 1233 first time mothers recruited at 20 weeks gestation we drew a stratified random sample of 316 for assessment at 32 weeks based on reported inter-partner psychological abuse, a risk to child development. Of these 271 provided data at 5, 9 and 29 weeks post delivery. Mothers reported how often they stroked their babies at 5 and 9 weeks. At 29 weeks vagal withdrawal to a stressor, a measure of physiological adaptability, and maternal reported negative emotionality were assessed. There was a significant interaction between prenatal depression and maternal stroking in the prediction of vagal reactivity to a stressor (p = .01), and maternal reports of infant anger proneness (p = .007) and fear (p = .043). Increasing maternal depression was associated with decreasing physiological adaptability, and with increasing negative emotionality, only in the presence of low maternal stroking. These initial findings in humans indicate that maternal stroking in infancy, as reported by mothers, has effects strongly resembling the effects of observed maternal behaviours in animals, pointing to future studies of the epigenetic, physiological and behavioral effects of maternal stroking.

Stress, glucocorticoids and liquorice in human pregnancy: programmers of the offspring brain

A suboptimal prenatal environment may induce permanent changes in cells, organs and physiology that alter social, emotional and cognitive functioning, and increase the risk of cardiometabolic and mental disorders in subsequent life ("developmental programming"). Although animal studies have provided a wealth of data on programming and its mechanisms, including on the role of stress and its glucocorticoid mediators, empirical evidence of these mechanisms in humans is still scanty. We review the existing human evidence on the effects of prenatal maternal stress, anxiety and depression, glucocorticoids and intake of liquorice (which inhibits the placental barrier to maternal glucocorticoids) on offspring developmental outcomes including, for instance, alterations in psychophysiological and neurocognitive functioning and mental health. This work lays the foundations for biomarker discovery and affords opportunities for prevention and interventions to ameliorate adverse outcomes in humans.

Challenges to maternal wellbeing during pregnancy impact temperament, attention, and neuromotor responses in the infant rhesus monkey

The relative maturity, alertness, and reactivity of an infant at birth are sensitive indices of the neonate's health, the quality of the pregnancy, and the mother's wellbeing. Even when fetal growth and gestation length have been normal, the maturing fetus can still be adversely impacted by both physical events and psychological challenges to the mother during the prenatal period. The following research evaluated 413 rhesus monkeys from 7 different types of pregnancies to determine which conditions significantly influenced the behavioral responsiveness and state of the young infant. A standardized test battery modeled after the Neonatal Behavioral Assessment Scale for human newborns was employed. The largest impairments in orientation and increases in infant emotional reactivity were seen when female monkeys drank alcohol, even though consumed at only moderate levels during part of the pregnancy. The infants' ability to focus and attend to visual and auditory cues was also affected when the gravid female's adrenal hormones were transiently elevated for 2 weeks by ACTH administration. In addition, responses to tactile and vestibular stimulation were altered by both this ACTH treatment and psychological disturbance during gestation. Conversely, a 2-day course of antenatal corticosteroids 1 month before term resulted in infants with lower motor activity and reactivity. These findings highlight several pregnancy conditions that can affect a young infant's neurobehavioral status, even when otherwise healthy, and demonstrate that alterations or deficits are specific to the type of insult experienced by the mother and fetus.