DHEA: a neglected biological signal that may affect fetal and child development

BACKGROUND

The stress-sensitive maternal hypothalamic-pituitary-adrenal (HPA) axis through the end-product cortisol, represents a primary pathway through which maternal experience shapes fetal development with long-term consequences for child neurodevelopment. However, there is another HPA axis end-product that has been widely ignored in the study of human pregnancy. The synthesis and release of dehydroepiandosterone (DHEA) is similar to cortisol, so it is a plausible, but neglected, biological signal that may influence fetal neurodevelopment. DHEA also may interact with cortisol to determine developmental outcomes. Surprisingly, there is virtually nothing known about human fetal exposure to prenatal maternal DHEA and offspring neurodevelopment. The current study examined, for the first time, the joint impact of fetal exposure to prenatal maternal DHEA and cortisol on infant emotional reactivity.

METHODS

Participants were 124 mother-infant dyads. DHEA and cortisol were measured from maternal hair at 15 weeks (early gestation) and 35 weeks (late gestation). Observational assessments of positive and negative emotional reactivity were obtained in the laboratory when the infants were 6 months old. Pearson correlations were used to examine the associations between prenatal maternal cortisol, prenatal maternal DHEA, and infant positive and negative emotional reactivity. Moderation analyses were conducted to investigate whether DHEA might modify the association between cortisol and emotional reactivity.

RESULTS

Higher levels of both early and late gestation maternal DHEA were linked to greater infant positive emotional reactivity. Elevated late gestation maternal cortisol was associated with greater negative emotional reactivity. Finally, the association between fetal cortisol exposure and infant emotional reactivity was only observed when DHEA was low.

CONCLUSIONS

These new observations indicate that DHEA is a potential maternal biological signal involved in prenatal programming. It appears to act both independently and jointly with cortisol to determine a child's emotional reactivity. Its role as a primary end-product of the HPA axis, coupled with the newly documented associations with prenatal development shown here, strongly calls for the inclusion of DHEA in future investigations of fetal programming.

What Do Your Neighbors Think About You? How Perceived Neighbor Attitudes Toward Latinos Influence Mental Health Among a Pregnant Latina Cohort

Latina women living in the USA experience disproportionately higher rates of psychological distress compared to their non-Latina White counterparts. Poor maternal mental health during pregnancy can contribute to intergenerational mental health disparities. Through this pathway, mothers' experiences, environments, and exposures (henceforth "exposures") during pregnancy become biologically embodied and can negatively affect the fetus and life-long developmental trajectories of her child. One of the exposures that can affect mother-offspring dyads is the neighborhood. With the goal of integrating anthropological and sociological theories to explain mental health disparities among pregnant Latina women, we explored how perceptions of neighbor attitudes may influence mental health during pregnancy. We analyzed self-reported responses from 239 pregnant Latina women in Southern California (131 foreign-born, 108 US-born) on their mental health and perceived attitudes of their neighbors using multiple linear regression models. Among foreign-born Latina women, living in neighborhoods with more favorable views of Latinos was associated with lower depression scores (pooled β =  - .70, SE = .29, p = .019) and lower pregnancy-related anxiety scores (pooled β =  - .11, SE = .05, p = .021), but greater state anxiety scores (pooled β = .09, SE = .04, p = .021). Among US-born women, there were no associations between neighbor attitudes and mental health. Overall, results suggest that social environments are correlated with mental health and that foreign-born and US-born Latinas have varied mental health experiences in the USA. Our findings highlight the importance of improving aspects of neighborhood cohesion as part of maternal-fetal care management.

Prenatal maternal Inflammation, childhood cognition and adolescent depressive symptoms

BACKGROUND

Accumulating evidence indicates that higher prenatal maternal inflammation is associated with increased depression risk in adolescent and adult-aged offspring. Prenatal maternal inflammation (PNMI) may increase the likelihood for offspring to have lower cognitive performance, which, in turn, may heighten risk for depression onset. Therefore, this study explored the potential mediating role of childhood cognitive performance in the relationship between PNMI and adolescent depressive symptoms in offspring.

METHODS

Participants included 696 mother-offspring dyads from the Child Health and Development Studies (CHDS) cohort. Biomarkers of maternal inflammation [interleukin (IL)-6, IL-8, IL-1 receptor antagonist (IL-1RA) and soluble TNF receptor-II (sTNF-RII)] were assayed from first (T1) and second trimester (T2) sera. Childhood (ages 9-11) cognitive performance was assessed via standardized Peabody Picture Vocabulary Test (PPVT), a measure of receptive vocabulary correlated with general intelligence. Adolescent (ages 15-17) depressive symptoms were assessed via self-report.

RESULTS

There were no significant associations between T1 biomarkers and childhood PPVT or adolescent depressive symptoms. Higher T2 IL1-RA was directly associated with lower childhood PPVT (b = -0.21, SE = 0.08, t = -2.55, p = 0.01), but not with adolescent depressive symptoms. T2 IL-6 was not directly associated with childhood PPVT, but higher T2 IL-6 was directly associated at borderline significance with greater depressive symptoms in adolescence (b = 0.05, SE = 0.03, t = 1.96, p = 0.05). Lower childhood PPVT predicted significantly higher adolescent depressive symptoms (b = -0.07, SE = 0.02, t = -2.99, p < 0.01). There was a significant indirect effect of T2 IL-1RA on adolescent depressive symptoms via childhood PPVT (b = 0.03, 95 % CI = 0.002-0.03) indicating a partially mediated effect. No significant associations were found with T2 sTNF-RII nor IL-8.

CONCLUSIONS

Lower childhood cognitive performance, such as that indicated by a lower PPVT score, represents a potential mechanism through which prenatal maternal inflammation contributes to adolescent depression risk in offspring.

A multilevel developmental psychopathology model of childbirth and the perinatal transition

Despite recent applications of a developmental psychopathology perspective to the perinatal period, these conceptualizations have largely ignored the role that childbirth plays in the perinatal transition. Thus, we present a conceptual model of childbirth as a bridge between prenatal and postnatal health. We argue that biopsychosocial factors during pregnancy influence postnatal health trajectories both directly and indirectly through childbirth experiences, and we focus our review on those indirect effects. In order to frame our model within a developmental psychopathology lens, we first describe "typical" biopsychosocial aspects of pregnancy and childbirth. Then, we explore ways in which these processes may deviate from the norm to result in adverse or traumatic childbirth experiences. We briefly describe early postnatal health trajectories that may follow from these birth experiences, including those which are adaptive despite traumatic childbirth, and we conclude with implications for research and clinical practice. We intend for our model to illuminate the importance of including childbirth in multilevel perinatal research. This advancement is critical for reducing perinatal health disparities and promoting health and well-being among birthing parents and their children.

Fetal brain growth and infant autistic traits

BACKGROUND

Structural differences exist in the brains of autistic individuals. To date only a few studies have explored the relationship between fetal brain growth and later infant autistic traits, and some have used fetal head circumference (HC) as a proxy for brain development. These findings have been inconsistent. Here we investigate whether fetal subregional brain measurements correlate with autistic traits in toddlers.

METHODS

A total of 219 singleton pregnancies (104 males and 115 females) were recruited at the Rosie Hospital, Cambridge, UK. 2D ultrasound was performed at 12-, 20- and between 26 and 30 weeks of pregnancy, measuring head circumference (HC), ventricular atrium (VA) and transcerebellar diameter (TCD). A total of 179 infants were followed up at 18-20 months of age and completed the quantitative checklist for autism in toddlers (Q-CHAT) to measure autistic traits.

RESULTS

Q-CHAT scores at 18-20 months of age were positively associated with TCD size at 20 weeks and with HC at 28 weeks, in univariate analyses, and in multiple regression models which controlled for sex, maternal age and birth weight.

LIMITATIONS

Due to the nature and location of the study, ascertainment bias could also have contributed to the recruitment of volunteer mothers with a higher than typical range of autistic traits and/or with a significant interest in the neurodevelopment of their children.

CONCLUSION

Prenatal brain growth is associated with toddler autistic traits and this can be ascertained via ultrasound starting at 20 weeks gestation.

Letter to the Editor: Does fetal movement shape the maternal brain?

Here, we debate that fetal behavior may contribute to the dynamic changes observed in the maternal brain during the perinatal period. We call for future research to explore this perspective to understand the complex maternal-fetal relationship and how fetal signals influence the preparation for parenthood.

Recalibration of the stress response system over adult development: Is there a perinatal recalibration period?

During early life-sensitive periods (i.e., fetal, infancy), the developing stress response system adaptively calibrates to match environmental conditions, whether harsh or supportive. Recent evidence suggests that puberty is another window when the stress system is open to recalibration if environmental conditions have shifted significantly. Whether additional periods of recalibration exist in adulthood remains to be established. The present paper draws parallels between childhood (re)calibration periods and the perinatal period to hypothesize that this phase may be an additional window of stress recalibration in adult life. Specifically, the perinatal period (defined here to include pregnancy, lactation, and early parenthood) is also a developmental switch point characterized by heightened neural plasticity and marked changes in stress system function. After discussing these similarities, lines of empirical evidence needed to substantiate the perinatal stress recalibration hypothesis are proposed, and existing research support is reviewed. Complexities and challenges related to delineating the boundaries of perinatal stress recalibration and empirically testing this hypothesis are discussed, as well as possibilities for future multidisciplinary research. In the theme of this special issue, perinatal stress recalibration may be a mechanism of multilevel, multisystem risk, and resilience, both intra-individually and intergenerationally, with implications for optimizing interventions.

Serotonin transporter (5-HTT) gene network moderates the impact of prenatal maternal adversity on orbitofrontal cortical thickness in middle childhood

In utero, the developing brain is highly susceptible to the environment. For example, adverse maternal experiences during the prenatal period are associated with outcomes such as altered neurodevelopment and emotion dysregulation. Yet, the underlying biological mechanisms remain unclear. Here, we investigate whether the function of a network of genes co-expressed with the serotonin transporter in the amygdala moderates the impact of prenatal maternal adversity on the structure of the orbitofrontal cortex (OFC) in middle childhood and/or the degree of temperamental inhibition exhibited in toddlerhood. T1-weighted structural MRI scans were acquired from children aged 6-12 years. A cumulative maternal adversity score was used to conceptualize prenatal adversity and a co-expression based polygenic risk score (ePRS) was generated. Behavioural inhibition at 18 months was assessed using the Early Childhood Behaviour Questionnaire (ECBQ). Our results indicate that in the presence of a low functioning serotonin transporter gene network in the amygdala, higher levels of prenatal adversity are associated with greater right OFC thickness at 6-12 years old. The interaction also predicts temperamental inhibition at 18 months. Ultimately, we identified important biological processes and structural modifications that may underlie the link between early adversity and future deviations in cognitive, behavioural, and emotional development.

Effect of Musical Stimulation on Placental Programming and Neurodevelopment Outcome of Preterm Infants: A Systematic Review

BACKGROUND

The fetal environment is modulated by the placenta, which integrates and transduces information from the maternal environment to the fetal developmental program and adapts rapidly to changes through epigenetic mechanisms that respond to internal (hereditary) and external (environmental and social) signals. Consequently, the fetus corrects the trajectory of own development. During the last trimester of gestation, plasticity shapes the fetal brain, and prematurity can alter the typical developmental trajectories. In this period, prevention through activity-inducing (e.g., music stimulation) interventions are currently tested. The purpose of this review is to describe the potentialities of music exposure on fetus, and on preterm newborns in the Neonatal Intensive Care Unit evaluating its influence on neurobehavioral development.

METHODS

Databases were searched from 2010 to 2022 for studies investigating mechanisms of placental epigenetic regulation and effects of music exposure on the fetus and pre-term neonates.

RESULTS

In this case, 28 selected papers were distributed into three research lines: studies on placental epigenetic regulation (13 papers), experimental studies of music stimulation on fetus or newborns (6 papers), and clinical studies on premature babies (9 papers). Placental epigenetic changes of the genes involved in the cortisol and serotonin response resulted associated with different neurobehavioral phenotypes in newborns. Prenatal music stimulation had positive effects on fetus, newborn, and pregnant mother while post-natal exposure affected the neurodevelopment of the preterm infants and parental interaction.

CONCLUSIONS

The results testify the relevance of environmental stimuli for brain development during the pre- and perinatal periods and the beneficial effects of musical stimulation that can handle the fetal programming and the main neurobehavioral disorders.

An evolutionary perspective on the association between grandmother-mother relationships and maternal mental health among a cohort of pregnant Latina women

Grandmothers are often critical helpers during a mother's reproductive career. Studies on the developmental origins of health and disease demonstrate how maternal psychological distress can negatively influence fetal development and birth outcomes, highlighting an area in which soon-to-be grandmothers (henceforth "grandmothers") can invest to improve both mother and offspring well-being. Here, we examine if and how a pregnant woman's mental health- specifically, depression, state-anxiety, and pregnancy-related anxiety- is influenced by her relationship with her fetus' maternal and paternal grandmother, controlling for relationship characteristics with her fetus' father. In a cohort of pregnant Latina women in Southern California (N = 216), we assessed social support, geographic proximity, and communication between the fetus' grandmothers and pregnant mother. We assessed maternal mental health with validated questionnaire-based instruments. We find that both social support from and communication with the maternal grandmother were statistically associated with less depression, while no paternal grandmother relationship characteristics were statistically significant in association with any mental health variable. These results align with the idea that maternal grandmothers are more adaptively incentivized to invest in their daughters' well-being during pregnancy than paternal grandmothers are for their daughters-in-law. Results suggest that the positive association of maternal grandmothers with mothers' mental health may not hinge on geographic proximity, but rather, potentially function through emotional support. This work represents a novel perspective describing a psychological and prenatal grandmaternal effect.

Post-weaning exposure to Sunset Yellow FCF induces behavioral impairment and structural changes in the adult rat medial prefrontal cortex: protective effects of Coenzyme Q10

Sunset Yellow FCF (E110) is a water soluble synthetic dye that has adverse neurobehavioral effects. Coenzyme Q10 (CoQ10) is known as a neuroprotective agent. The present study aimed to evaluate the effects of post-weaning exposure to Sunset Yellow FCF on behavioral and structural changes in the adult rat medial prefrontal cortex and the protective effects of CoQ10. The weanling rats were randomly divided into six groups: distilled water, CoQ10 (10 mg/kg/day), and low (2.5 mg/kg/day), and high (70 mg/kg/day) doses of Sunset Yellow FCF with or without CoQ10 consumption for six weeks. A battery of behavioral tests including open field and Morris water maze tests were done at the end of the 6th week, and then the animals' brains were removed for stereological methods. Our finding indicated that the high dose of Sunset Yellow FCF led to a reduced total volume of mPFC (15.16%), especially in the anterior cingulate cortex (ACC) region (21.96%), along with loss of neurons (32%) and glial cells (37%), which was associated with higher anxiety behavior and loss in spatial memory. However, CoQ10 prevented the neural loss and glial cells, improved anxiety like behaviors and memory impairment. On the other hand, the acceptable daily dose (low dose of Sunset Yellow FCF) did not show a discernible effect on the same parameters. This study showed that the CoQ10 can protect the alteration in mPFC structure and behavioral changes of the rats exposed to high dose of Sunset Yellow FCF.

Prenatal mother-father cortisol linkage predicts infant executive functions at 24 months

The present study investigated associations between prenatal mother-father cortisol linkage and infant executive functions. Data come from an international sample (N = 358) of predominantly white and middle- to upper-class first-time parents. During late pregnancy, parents collected diurnal salivary cortisol samples and reported on levels of psychological stress. At 24 months, children completed a battery of executive function tasks. Parent cortisol linkage was operationalized as the time-dependent, within-dyad association between maternal and paternal diurnal cortisol. Results indicated that prenatal linkage was positively related to infant executive functions, suggesting that stronger mother-father cortisol linkage was associated with higher executive function scores. Additionally, this relation was moderated by paternal average cortisol levels such that executive function scores were lower when fathers had higher average cortisol levels and linkage was weak. This association suggests that elevated paternal cortisol amplifies the negative relation between lower cortisol linkage and lower infant executive function scores. Importantly, these findings were observed while controlling for observational measures of caregiving and self-report measures of psychosocial functioning and infant social-emotional behavior. These results suggest that prenatal linkage of mother's and father's stress physiology plays a potentially important part in programming and regulating infant neurocognitive development.

Yawning Is More Contagious in Pregnant Than Nulliparous Women : Naturalistic and Experimental Evidence

Contrary to spontaneous yawning, which is widespread in vertebrates and probably evolutionary ancient, contagious yawning—yawning triggered by others’ yawns—is considered an evolutionarily recent phenomenon, found in species characterized by complex sociality. Whether the social asymmetry observed in the occurrence of contagious yawning is related to social and emotional attachment and may therefore reflect emotional contagion is a subject of debate. In this study we assessed whether yawn contagion was enhanced in pregnant women, a cohort of subjects who develop prenatal emotional attachment in preparation for parental care, via hormonal and neurobiological changes. We predicted that if yawn contagion underlies social and emotional attachment, pregnant women would be more likely to contagiously yawn than nonpregnant, nulliparous women of reproductive age. We gathered data in two different settings. In the experimental setting, 49 women were exposed to video stimuli of newborns either yawning or moving their mouth (control) and we video-recorded the women during repeated trials to measure their yawning response. In the naturalistic setting, 131 women were observed in a social environment and their yawning response was recorded. We tested the factors influencing the yawning response, including the reproductive status (pregnant vs. not pregnant). In both settings, yawn contagion occurred significantly more in pregnant than nonpregnant women. By showing that pregnant women were most likely to respond to others’ yawns, our results support the hypothesis that the social variation observed in yawn contagion may be influenced by emotional attachment and that yawning in highly social species might have been coopted for emotional contagion during evolution.

Influences of adversity across the lifespan on respiratory sinus arrhythmia during pregnancy

There is limited understanding of factors across the lifespan that influence pregnant women's respiratory sinus arrhythmia (RSA), which could have implications for their health and offspring development. We examined associations among 162 English- and Spanish-speaking pregnant women's childhood maltreatment history, emotion dysregulation, recent life stress, and resting RSA during the third trimester. Moderated mediation analyses indicated that more severe childhood maltreatment history (95% confidence interval (CI) [0.26, 0.63]) and higher emotion dysregulation (95% CI [0.001, 0.006]) predicted more stress during pregnancy, and childhood maltreatment history interacted with emotion dysregulation to predict resting RSA (95% CI [-0.04, -0.0003]). Exploratory analyses revealed that women's health-related stress during pregnancy mediated the relation between emotion dysregulation and RSA regardless of childhood maltreatment severity (95% CI [-0.007, -0.002]). These findings suggest that women's resting RSA during pregnancy may reflect physical and emotional stress accumulation across the lifespan and that relations between early life adversity and prenatal psychophysiology may be buffered by protective factors, such as emotion regulation. In addition, these findings underscore the importance of distinguishing between types of prenatal stress. Given the implications for women's health and offspring development, we urge researchers to continue exploring factors associated with pregnant women's psychophysiology.

Maternal psychological stress moderates diurnal cortisol linkage in expectant fathers and mothers during late pregnancy

Using data from a large international sample (N = 385) of first-time expectant parents, the current analysis investigated whether parents demonstrated diurnal cortisol linkage in late pregnancy and whether self-reported psychological stress moderated this linkage. At approximately 36 weeks gestation, mothers and fathers collected saliva samples in their home at three times on two consecutive days and reported on their psychological stress. Results from multilevel models indicated that there was significant positive within-couple diurnal cortisol linkage on average for the whole sample. However, this linkage was moderated by maternal self-reported psychological stress. Specifically, for couples with higher maternal psychological stress, cortisol linkage was strong. Conversely, for couples with lower maternal psychological stress, maternal and paternal cortisol were unrelated. These findings suggest that among higher-maternal-stress couples, lower paternal cortisol may buffer maternal cortisol, whereas higher paternal cortisol may amplify maternal cortisol. Our results support the idea that interpersonal psychological and physiological stress in close relationships is interdependent and mutually influenced. Further, our findings contribute to the field's understanding of interpersonal processes during pregnancy, which may have health-related implications in the prenatal and postnatal periods for both parents and the developing child.

Transcriptional and epigenetic changes of brain derived neurotrophic factor following prenatal stress: A systematic review of animal studies

Gestational period plays critical role in neuropsychological development. One of the genes that undergoes changes by prenatal stress (PNS) exposure, is the gene coding brain derived neurotrophic factor (BDNF). Studies have reported different patterns of change following PNS in BDNF, which emphasizes the complexity of the issue. In this review, systematic search of PubMed, Scopus, Web of Science and Cochrane CENTRAL databases was performed. Primary searches resulted in 2132 studies and finally 43 studies were found to meet the inclusion criteria. Transcriptional and epigenetic changes of BDNF gene in the brain were recorded. Decreased or unchanged BDNF total mRNA and BDNF mature protein, with hypermethylation of the coding exons were the most reported changes. However, stress paradigm, gender of the fetus and the day of sacrifice were found to significantly affect the results. Hippocampus and prefrontal cortex are the most vulnerable regions. They can show long lasting and persistent transcriptional and epigenetics changes of BDNF gene following PNS. Further studies evaluating the importance of these findings in humans are essential.

Prenatal exposure to artificial food colorings alters NMDA receptor subunit concentrations in rat hippocampus

Exposure to artificial food color additives (AFCAs) has been implicated in the etiology of certain childhood hyperactivity and learning disabilities. N-methyl-D-aspartate receptors and alpha-7 nicotinic acetylcholine receptor (α7 nAChR) are involved in learning and memory. We administered a mixture of AFCAs (erythrosine, ponceau 4R, allura red AC, sunset yellow FCF, tartrazine, amaranth, brilliant blue, azorubine, and indigotine) to female rats during gestation to investigate the effects of prenatal exposure to AFCAs on neurobehavior, spatial learning, and memory in their offspring. We also investigated whether AFCAs modulate NR2A, NR2B, and α7 nAChR protein levels in their offsprings' hippocampi. Although spatial learning and memory were not altered, the offspring of rats exposed to AFCAs exhibited decreased motivation and increased despair-related behavior. NR2A and NR2B protein levels were significantly reduced in female offspring in the experimental group (p < 0.05), whereas α7 nAChR level was not significantly altered. Our results suggest that prenatal exposure to AFCAs may lead to sex-dependent alterations in glutamatergic signaling which may continue into adolescence.

Intergenerational transmission of emotion dysregulation: Part I. Psychopathology, self-injury, and parasympathetic responsivity among pregnant women

The World Health Organization recently reported that maternal mental health is a major public health concern. As many as one in four women suffer from psychiatric disorders at some point during pregnancy or the first postpartum year. Furthermore, self-injurious thoughts and behaviors (SITBs) represent one of the leading causes of death among women during this time. Thus, efforts to identify women at risk for serious forms of psychopathology and especially for SITBs are of utmost importance. Despite this urgency, current single-diagnostic approaches fail to recognize a significant subset of women who are vulnerable to perinatal stress and distress. The current study was among the first to investigate emotion dysregulation-a multilevel, transdiagnostic risk factor for psychopathology-and its associations with stress, distress, and SITBs in a sample of pregnant women (26-40 weeks gestation) recruited to reflect a range of emotion dysregulation. Both self-reported emotion dysregulation and respiratory sinus arrhythmia, a biomarker of emotion dysregulation, demonstrated expected associations with measures of mental health, including depression, anxiety, borderline personality pathology, and SITBs. In addition, self-reported emotion dysregulation was associated with blunted respiratory sinus arrhythmia responsivity to an ecologically valid infant cry task. Findings add to the literature considering transdiagnostic risk during pregnancy using a multiple-levels-of-analysis approach.

Maternal programming: Application of a developmental psychopathology perspective

The fetal phase of life has long been recognized as a sensitive period of development. Here we posit that pregnancy represents a simultaneous sensitive period for the adult female with broad and persisting consequences for her health and development, including risk for psychopathology. In this review, we examine the transition to motherhood through the lens of developmental psychopathology. Specifically, we summarize the typical and atypical changes in brain and behavior that characterize the perinatal period. We highlight how the exceptional neuroplasticity exhibited by women during this life phase may account for increased vulnerability for psychopathology. Further, we discuss several modes of signaling that are available to the fetus to affect maternal phenotypes (hormones, motor activity, and gene transfer) and also illustrate how evolutionary perspectives can help explain how and why fetal functions may contribute to maternal psychopathology. The developmental psychopathology perspective has spurred advances in understanding risk and resilience for mental health in many domains. As such, it is surprising that this major epoch in the female life span has yet to benefit fully from similar applications.

Echoes of Early Life: Recent Insights From Mathematical Modeling

In the last decades, developmental origins of health and disease (DOHaD) has emerged as a central framework for studying early‐life effects, that is, the impact of fetal and early postnatal experience on adult functioning. Apace with empirical progress, theoreticians have built mathematical models that provide novel insights for DOHaD. This article focuses on three of these insights, which show the power of environmental noise (i.e., imperfect indicators of current and future conditions) in shaping development. Such noise can produce: (a) detrimental outcomes even in ontogenetically stable environments, (b) individual differences in sensitive periods, and (c) early‐life effects tailored to predicted future somatic states. We argue that these insights extend DOHaD and offer new research directions.

Effects of pre- and postnatal maternal stress on infant temperament and autonomic nervous system reactivity and regulation in a diverse, low-income population

We examined the prospective associations of objective and subjective measures of stress during pregnancy with infant stress reactivity and regulation, an early-life predictor of psychopathology. In a racially and ethnically diverse low-income sample of 151 mother-infant dyads, maternal reports of stressful life events (SLE) and perceived stress (PS) were collected serially over gestation and the early postpartum period. Infant reactivity and regulation at 6 months of age was assessed via maternal report of temperament (negativity, surgency, and regulation) and infant parasympathetic nervous system physiology (respiratory sinus arrhythmia [RSA]) during the Still Face Paradigm. Regression models predicting infant temperament showed higher maternal prenatal PS predicted lower surgency and self-regulation but not negativity. Regression models predicting infant physiology showed higher numbers of SLE during gestation predicted greater RSA reactivity and weaker recovery. Tests of interactions revealed SLE predicted RSA reactivity only at moderate to high levels of PS. Thus, findings suggest objective and subjective measures of maternal prenatal stress uniquely predict infant behavior and physiology, adjusting for key pre- and postnatal covariates, and advance the limited evidence for such prenatal programming within high-risk populations. Assessing multiple levels of maternal stress and offspring stress reactivity and regulation provides a richer picture of intergenerational transmission of adversity.

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 sensitivity and social support protect against childhood atopic dermatitis

BACKGROUND

Many studies have identified associations between qualities of maternal-child relationships and childhood asthma, but few have examined associations with childhood atopic dermatitis (AD), a common precursor to asthma. Moreover, maternal psychological distress, including prenatal and postnatal depression, anxiety and stress, may increase risk, while social support from partners may reduce risk for childhood AD. We sought to uncover the association between maternal-infant relationship qualities (maternal sensitivity towards infant behavioral signals, controlling behavior, and unresponsiveness) and child AD after accounting for risk (i.e., prenatal and postnatal maternal depression, anxiety and stress) and protective (i.e., social support) factors.

METHODS

We conducted a secondary analysis of data collected on a subsample of 242 women and their infants enrolled during pregnancy in the ongoing Alberta Pregnancy Outcomes and Nutrition cohort study. Inclusion criteria required mothers to be >16 years of age, English speaking and <22 weeks gestational age at enrollment. Data on depression, anxiety and stress in the prenatal and postnatal periods and physician diagnosis of childhood AD at 18 months were gathered via maternal report. Maternal sensitivity, unresponsiveness and controlling behaviours were assessed via videotaped observations using the Child-Adult Relationship Experimental (CARE)-Index at 6 months of infant age.

RESULTS

Higher maternal sensitivity, or the inability of the mother to appropriately understand and respond to infant needs based on behavioral signals, predicted reduced odds of AD independent of and in combination with low prenatal and postnatal anxiety and high paternal support. After adjustment, higher maternal controlling behaviours and unresponsiveness also predicted greater odds of AD.

CONCLUSIONS

Low maternal sensitivity is a risk factor for childhood AD, independently and in combination with perinatal anxiety and low social support. Thus, interventions that improve maternal-infant relationship quality, especially sensitivity, reduce anxiety and improve social support from partners could reduce odds of childhood AD.

Biological embedding of perinatal social relationships in infant stress reactivity

Whereas significant advances have been made in understanding how exposure to early adversity "gets under the skin" of children to result in long term changes in developmental outcomes, the processes by which positive social relationships become biologically embedded remain poorly understood. The aim of this study was to understand the pathways by which maternal and infant social environments become biologically embedded in infant cortisol reactivity. Two hundred seventy-two pregnant women and their infants were prospectively assessed during pregnancy and at 6 months postpartum. In serial mediation analyses, higher perceived social support from partners during pregnancy was associated with lower infant cortisol reactivity or larger decreases in cortisol in response to a stressor at 6 months of age via lower self-reported prenatal maternal depression and higher mother-infant interaction quality. The findings add to our understanding of how perinatal social relationships become biologically embedded in child development.

Fetal sex is associated with maternal stimulated cytokine production, but not serum cytokine levels, in human pregnancy

Some studies suggest that fetal sex plays a role in maternal physiological processes during pregnancy including glycemic control, blood pressure, and cortisol regulation. However, data examining fetal sex-specific differences in maternal immune parameters is lacking. In the current study, serum levels of interleukin(IL)-6, IL-8, and tumor necrosis factor(TNF)-α as well as LPS-stimulated production of IL-6, IL-8, TNF-α, and IL-1β by PBMCs incubated for 24h were assessed in early, mid, and late pregnancy among 80 women (46 with male and 34 with female fetuses). Linear mixed models showed that women carrying females versus males exhibited greater stimulated production of IL-6 at each timepoint (ps⩽0.03), TNF-α in early pregnancy (p=0.04), and IL-1β in mid- and late pregnancy (ps⩽0.05). Despite changes in serum levels of IL-8 (p=0.002) and TNF-α (p<0.0001) across pregnancy, no differences in any serum cytokines were observed in relation to fetal sex (ps>0.85). In conclusion, in pregnant women, those carrying female versus male fetuses exhibited greater stimulated cytokine production across pregnancy. Differential inflammatory responses could affect maternal health and fetal development. Fetal sex should be considered as a factor in studies of maternal inflammation. These findings have relevance both clinically and conceptually. For example, maternal asthma is exacerbated among women carrying female versus male fetuses. In addition, data on associations between fetal sex and maternal immune function among women with health conditions (e.g., preeclampsia) and adverse pregnancy outcomes (e.g., preterm birth) would be informative.

Maternal prenatal depression is associated with decreased placental expression of the imprinted gene PEG3

BACKGROUND

Maternal prenatal stress during pregnancy is associated with fetal growth restriction and adverse neurodevelopmental outcomes, which may be mediated by impaired placental function. Imprinted genes control fetal growth, placental development, adult behaviour (including maternal behaviour) and placental lactogen production. This study examined whether maternal prenatal depression was associated with aberrant placental expression of the imprinted genes paternally expressed gene 3 (PEG3), paternally expressed gene 10 (PEG10), pleckstrin homology-like domain family a member 2 (PHLDA2) and cyclin-dependent kinase inhibitor 1C (CDKN1C), and resulting impaired placental human placental lactogen (hPL) expression.

METHOD

A diagnosis of depression during pregnancy was recorded from Manchester cohort participants' medical notes (n = 75). Queen Charlotte's (n = 40) and My Baby and Me study (MBAM) (n = 81) cohort participants completed the Edinburgh Postnatal Depression Scale self-rating psychometric questionnaire. Villous trophoblast tissue samples were analysed for gene expression.

RESULTS

In a pilot study, diagnosed depression during pregnancy was associated with a significant reduction in placental PEG3 expression (41%, p = 0.02). In two further independent cohorts, the Queen Charlotte's and MBAM cohorts, placental PEG3 expression was also inversely associated with maternal depression scores, an association that was significant in male but not female placentas. Finally, hPL expression was significantly decreased in women with clinically diagnosed depression (44%, p < 0.05) and in those with high depression scores (31% and 21%, respectively).

CONCLUSIONS

This study provides the first evidence that maternal prenatal depression is associated with changes in the placental expression of PEG3, co-incident with decreased expression of hPL. This aberrant placental gene expression could provide a possible mechanistic explanation for the co-occurrence of maternal depression, fetal growth restriction, impaired maternal behaviour and poorer offspring outcomes.

Transfer entropy analysis of maternal and fetal heart rate coupling

Although evidence of the short term relationship between maternal and fetal heart rates has been found in previous model-based studies, knowledge about the mechanism and patterns of the coupling during gestation is still limited. In this study, a model-free method based on Transfer Entropy (TE) was applied to quantify the maternal-fetal heart rate couplings in both directions. Furthermore, analysis of the lag at which TE was maximum and its changes throughout gestation, provided more information about the mechanism of coupling and its latency. Experimental results based on fetal electrocardiograms (fECGs) and maternal ECG showed the evidence of coupling for 62 out of 65 healthy mothers and fetuses in each direction, by statistically validating against the surrogate pairs. The fetuses were divided into three gestational age groups: early (16-25 weeks), mid (26-31 weeks) and late (32-41 weeks) gestation. The maximum TE from maternal to fetal heart rate significantly increased from early to mid gestation, while the coupling delay on both directions decreased significantly from mid to late gestation. These changes occur concomitant with the maturation of the fetal sensory and autonomic nervous systems with advancing gestational age. In conclusion, the application of TE with delays revealed detailed information about the changes in fetal-maternal heart rate coupling strength and latency throughout gestation, which could provide novel clinical markers of fetal development and well-being.

A Role for the Placenta in Programming Maternal Mood and Childhood Behavioural Disorders

Substantial data demonstrate that the early-life environment, including in utero, plays a key role in later life disease. In particular, maternal stress during pregnancy has been linked to adverse behavioural and emotional outcomes in children. Data from human cohort studies and experimental animal models suggest that modulation of the developing epigenome in the foetus by maternal stress may contribute to the foetal programming of disease. Here, we summarise insights gained from recent studies that may advance our understanding of the role of the placenta in mediating the association between maternal mood disorders and offspring outcomes. First, the placenta provides a record of exposures during pregnancy, as indicated by changes in the placental trancriptome and epigenome. Second, prenatal maternal mood may alter placental function to adversely impact foetal and child development. Finally, we discuss the less well established but interesting possibility that altered placental function, more specifically changes in placental hormones, may adversely affect maternal mood and later maternal behaviour, which can also have consequence for offspring well-being.

Maternal prenatal stress and infant emotional reactivity six months postpartum

BACKGROUND

Maternal prenatal stress has been related to infant negative affect. However, it is still unclear how different sources of maternal prenatal stress such as depressive, anxiety and pregnancy-specific anxiety symptoms are associated with reactivity outcomes. This study aimed to test the associations between different sources of maternal prenatal stress and the aspects of infant emotional reactivity at six months.

METHOD

Our study population (n=282) was drawn from the FinnBrain Birth Cohort Study. Prenatal stress was measured by questionnaires on maternal depression, general anxiety and pregnancy-specific anxiety at three time points across pregnancy (gwk 14, 24, 34). Based on the symptom scores, the sample was divided into mothers with high stress during pregnancy (n=110) and mothers with low stress during pregnancy (n=172). Mother-reported infant emotional reactivity and its subscales were measured six months postpartum.

RESULTS

After controlling for background variables and maternal postnatal symptoms, overall negative emotional reactivity (β=0.20, p<0.01), and its aspects fearfulness (β=0.15, p=.057) and falling reactivity (β=-0.22, p<0.01), were predicted by only pregnancy-specific anxiety. No significant predictors were found for infant positive reactivity after adjusting for confounders.

LIMITATIONS

Mother reports of both maternal symptoms and infant reactivity were used, which might increase the risk of reporting bias.

CONCLUSIONS

The findings suggest that mothers experiencing stress should be provided intervention during pregnancy, and that screening should have a particular focus on pregnancy-related worries.

MYSTERIES OF THE HUMAN FETUS REVEALED

The impressive program of research from the DiPietro laboratory succeeds in its aim to document the ontogeny of human fetal neurobehavioral development. From studies of great depth and breadth, and wielding creative methods of assessment, DiPietro et al. open a window into the largely inaccessible developing human fetal brain. This commentary, with reference to the seminal cardiovascular studies of the Laceys, supports the measures of the fetal heart to index fetal well-being and to provide evidence of stimulus processing. A separate case is made that the DiPietro program provides unique and invaluable information for assessing the influential Developmental Origins of Health and Disease or Fetal Programming Models. The goal of these models, to predict or understand the influences of early experience or response patterns on later postnatal life, is identical to the ultimate goal of the DiPietro program. Because human fetal behavior is uncontaminated by socialization or parenting or peers, it may be the best reflection of fetal exposures. The remarkable neurobehavioral profiles generated by the DiPietro program can make a critical contribution to the Fetal Programming Model in terms of sensitive and critical periods of nervous system vulnerability and to specify gestational periods of neurobehavioral risk.

Fetal exposure to placental corticotropin-releasing hormone (pCRH) programs developmental trajectories

The maternal endocrine stress system is profoundly altered during the course of human pregnancy. The human placenta expresses the genes for CRH as early as the seventh week of gestation and it is the expotential increase in placental CRH (pCRH) over the course of human gestation that is responsible for the greatest modification in the maternal stress system. The bi-directional placental release of hormones into the maternal and fetal compartments has profound influences for both. The influential Fetal Programming model predicted that early or fetal exposures to maternal signals of threat or adverse conditions have lifelong consequences for health outcomes. A basic assumption of this model was that developing organisms play a dynamic role in their own construction. Data are reviewed and new data are presented that elevated pCRH over the course of human gestation plays a fundamental role in the organization of the fetal nervous system, modifies birth phenotype (the timing of the onset of spontaneous labor and delivery), and influences developmental, temperamental and metabolic trajectories. Evidence for sex differences and conserved function across species is presented. Finally, a model is presented that proposes several pathways that pCRH can program risk for health and disease.

Sexually dimorphic adaptations in basal maternal stress physiology during pregnancy and implications for fetal development

There is clear evidence of reciprocal exchange of information between the mother and fetus during pregnancy but the majority of research in this area has focussed on the fetus as a recipient of signals from the mother. Specifically, physiological signals produced by the maternal stress systems in response to the environment may carry valuable information about the state of the external world. Prenatal stress produces sex-specific adaptations within fetal physiology that have pervasive and long-lasting effects on development. Little is known, however, about the effects of sex-specific fetal signals on maternal adaptations to pregnancy. The current prospective study examined sexually dimorphic adaptations within maternal stress physiology, including the hypothalamic-adrenal-pituitary (HPA) axis and the autonomic nervous system (ANS) and associations with fetal growth. Using diurnal suites of saliva collected in early and late pregnancy, we demonstrate that basal cortisol and salivary alpha-amylase (sAA) differ by fetal sex. Women carrying female fetuses displayed greater autonomic arousal and flatter (but more elevated) diurnal cortisol patterns compared to women carrying males. Women with flatter daytime cortisol trajectories and more blunted sAA awakening responses also had infants with lower birth weight. These maternal adaptations are consistent with sexually dimorphic fetal developmental/evolutionary adaptation strategies that favor growth for males and conservation of resources for females. The findings provide new evidence to suggest that the fetus contributes to maternal HPA axis and ANS regulation during pregnancy and that these systems also contribute to the regulation of fetal growth.

Longer gestation among children born full term influences cognitive and motor development

Children born preterm show persisting impairments in cognitive functioning, school achievement, and brain development. Most research has focused on implications of birth prior to 37 gestational weeks; however, the fetal central nervous system continues to make fundamental changes throughout gestation. Longer gestation is associated with reduced morbidity and mortality even among infants born during the period clinically defined as full term (37-41 gestational weeks). The implications of shortened gestation among term infants for neurodevelopment are poorly understood. The present study prospectively evaluates 232 mothers and their full term infants (50.4% male infants) at three time points across the first postnatal year. We evaluate the association between gestational length and cognitive and motor development. Infants included in the study were full term (born between 37 and 41 weeks gestation). The present study uses the combination of Last Menstrual Period (LMP) and early ultrasound for accurate gestational dating. Hierarchical Linear Regression analyses revealed that longer gestational length is associated with higher scores on the Bayley scales of mental and motor development at 3, 6 and 12 months of age after considering socio-demographic, pregnancy, and infant-level covariates. Findings were identical using revised categories of early, term, and late term proposed by the Working Group for Defining Term Pregnancy. Our findings indicate that longer gestation, even among term infants, benefits both cognitive and motor development.

Prenatal maternal stress predicts autism traits in 6½ year-old children: Project Ice Storm

Research implicates prenatal maternal stress (PNMS) as a risk factor for neurodevelopmental disorders; however few studies report PNMS effects on autism risk in offspring. We examined, prospectively, the degree to which objective and subjective elements of PNMS explained variance in autism-like traits among offspring, and tested moderating effects of sex and PNMS timing in utero. Subjects were 89 (46F/43M) children who were in utero during the 1998 Quebec Ice Storm. Soon after the storm, mothers completed questionnaires on objective exposure and subjective distress, and completed the Autism Spectrum Screening Questionnaire (ASSQ) for their children at age 6½. ASSQ scores were higher among boys than girls. Greater objective and subjective PNMS predicted higher ASSQ independent of potential confounds. An objective-by-subjective interaction suggested that when subjective PNMS was high, objective PNMS had little effect; whereas when subjective PNMS was low, objective PNMS strongly affected ASSQ scores. A timing-by-objective stress interaction suggested objective stress significantly affected ASSQ in first-trimester exposed children, though less so with later exposure. The final regression explained 43% of variance in ASSQ scores; the main effect of sex and the sex-by-PNMS interactions were not significant. Findings may help elucidate neurodevelopmental origins of non-clinical autism-like traits from a dimensional perspective.

Evaluation of the association between placental corticotrophin-releasing hormone and postpartum depressive symptoms

OBJECTIVE

Postpartum depression (PPD) represents a significant threat to maternal-child health. Although PPD is common, with an estimated prevalence of 10% to 15%, critical questions concerning its etiology remain unanswered. Existing studies seem to provide conflicting evidence regarding the relation between placental corticotrophin-releasing hormone (pCRH) and the development of PPD. The purpose of the present investigation was to determine whether maternal prepartum hypothalamic-pituitary-adrenal and placental dysregulation, in particular elevated midgestational pCRH, represent markers of risk for the development of PPD symptoms.

METHODS

One hundred seventy adult women with singleton, term pregnancies were recruited during the first trimester and participated in study visits at 15, 19, 25, 31, and 36+ weeks' gestation and at 3 and 6 months postpartum. At each prenatal visit, blood samples were obtained and assayed to determine maternal cortisol, adrenocorticotropic hormone, and pCRH concentrations. Depressive symptoms were assessed at all visits.

RESULTS

Depressive symptoms at 3 months postpartum were associated with elevated midgestational pCRH (partial r = 0.26; p < .01) and also accelerated trajectories of pCRH (B values ranged from 6.9 to 8.3, p < .05). Placental CRH was not predictive of PPD symptoms at 6 months postpartum. Furthermore, prepartum cortisol and corticotrophin profiles were not associated with PPD symptoms.

CONCLUSIONS

The current prospective study provides results that reconcile both the positive and negative findings in the existing literature and identifies elevated pCRH as a marker of risk for the development of PPD symptoms.

Beyond risk, resilience, and dysregulation: Phenotypic plasticity and human development

We provide a theoretical and empirical basis for the claim that individual differences exist in developmental plasticity and that phenotypic plasticity should be a subject of study in its own right. To advance this argument, we begin by highlighting challenges that evolutionary thinking poses for a science of development and psychopathology, including for the diathesis–stress framework that has (fruitfully) guided so much empirical inquiry on developmental risk, resilience, and dysregulation. With this foundation laid, we raise a series of issues that the differential-susceptibility hypothesis calls attention to, while highlighting findings that have emerged over just the past several years and are pertinent to some of the questions posed. Even though it is clear that this new perspective on Person × Environment interaction is stimulating research and influencing how hypotheses are framed and data interpreted, a great many topics remain that need empirical attention. Our intention is to encourage students of development and psychopathology to treat phenotypic plasticity as an individual-difference construct while exploring unknowns in the differential-susceptibility equation.

Physiological reactivity of pregnant women to evoked fetal startle

OBJECTIVE

The bidirectional nature of mother-child interaction is widely acknowledged during infancy and childhood. Prevailing models during pregnancy focus on unidirectional influences exerted by the pregnant woman on the developing fetus. Prior work has indicated that the fetus also affects the pregnant woman. Our objective was to determine whether a maternal psychophysiological response to stimulation of the fetus could be isolated.

METHODS

Using a longitudinal design, an airborne auditory stimulus was used to elicit a fetal heart rate and motor response at 24 (n=47) and 36 weeks (n=45) of gestation. Women were blind to condition (stimulus versus sham). Maternal parameters included cardiac (heart rate) and electrodermal (skin conductance) responses. Multilevel modeling of repeated measures with 5 data points per second was used to examine fetal and maternal responses.

RESULTS

As expected, compared to a sham condition, the stimulus generated a fetal motor response at both gestational ages, consistent with a mild fetal startle. Fetal stimulation was associated with significant, transient slowing of maternal heart rate coupled with increased skin conductance within 10s of the stimulus at both gestational ages. Nulliparous women showed greater electrodermal responsiveness. The magnitude of the fetal motor response significantly corresponded to the maternal skin conductance response at 5, 10, 15, and 30s following stimulation.

CONCLUSION

Elicited fetal movement exerts an independent influence on the maternal autonomic nervous system. This finding contributes to current models of the dyadic relationship during pregnancy between fetus and pregnant woman.

Does Early-Life Exposure to Stress Shape or Impair Cognition?

A predominant view in psychology is that early psychosocial adversity (e.g., abuse) impairs cognition, because children from stressful backgrounds (e.g., violent households) score lower on standard tests of intelligence, language, memory, inhibition, and other abilities. However, recent studies indicate that these people may exhibit improved detection, learning, and memory on tasks involving stimuli that are ecologically relevant to them (e.g., dangers), compared with safely nurtured peers. These findings contradict the view that cognition of stressed people is generally impaired; they suggest, rather, that these people’s minds are developmentally specialized toward local environmental conditions. Here, we review recent research supporting this hypothesis. In addition, we propose that novel studies should examine whether stressed children show not only improved detection but also improved memory and reasoning on tasks involving stimuli that are ecologically relevant to them. Finally, we discuss clinical implications of switching from conceptualizing stressed minds as “adapted” rather than “impaired.”

Critical need for family-based, quasi-experimental designs in integrating genetic and social science research

Researchers have identified environmental risks that predict subsequent psychological and medical problems. Based on these correlational findings, researchers have developed and tested complex developmental models and have examined biological moderating factors (e.g., gene-environment interactions). In this context, we stress the critical need for researchers to use family-based, quasi-experimental designs when trying to integrate genetic and social science research involving environmental variables because these designs rigorously examine causal inferences by testing competing hypotheses. We argue that sibling comparison, offspring of twins or siblings, in vitro fertilization designs, and other genetically informed approaches play a unique role in bridging gaps between basic biological and social science research. We use studies on maternal smoking during pregnancy to exemplify these principles.

Increasing parity is associated with cumulative effects on memory

BACKGROUND

The purpose of this investigation was to determine if reproductive experience is associated with cumulative effects on human memory performance during pregnancy and if these effects persist into the postpartum period.

METHODS

Verbal recall memory performance was assessed in 254 women four times during pregnancy and at 3 months postpartum. The relation between parity and memory function was evaluated with hierarchical linear modeling and analysis of covariance (ANCOVA).

RESULTS

The data indicate that the previously documented adverse effects of pregnancy on memory performance are compounded with successive pregnancies. During gestation and postpartum, multiparity was associated with poorer memory function, and these effects did not appear to be due to differences in maternal demographics, depressive symptoms, or sleep quality.

CONCLUSIONS

Animal models demonstrate that the effects of reproduction on brain structure and function are both cumulative and enduring. However, little is known about the influence of reproductive experience on the human female brain. These findings provide evidence that in humans, reproduction is associated with striking and perhaps persisting changes in cognitive function.

Neurobehavioral risk is associated with gestational exposure to stress hormones

The developmental origins of disease or fetal programming model predict that early exposures to threat or adverse conditions have lifelong consequences that result in harmful outcomes for health. The maternal endocrine 'fight or flight' system is a source of programming information for the human fetus to detect threats and adjust their developmental trajectory for survival. Fetal exposures to intrauterine conditions including elevated stress hormones increase the risk for a spectrum of health outcomes depending on the timing of exposure, the timetable of organogenesis and the developmental milestones assessed. Recent prospective studies, reviewed here, have documented the neurodevelopmental consequences of fetal exposures to the trajectory of stress hormones over the course of gestation. These studies have shown that fetal exposures to biological markers of adversity have significant and largely negative consequences for fetal, infant and child emotional and cognitive regulation and reduced volume in specific brain structures.

A placenta for life

The chorioallantoic placenta is the defining organ of eutherians that has enabled prolonged intrauterine gestation. As such, normal placental development and function are essential for mammalian reproductive success. Reflecting the key role of this organ in providing nutrients to the embryo, the characteristic cell type that forms substantial parts of the placenta is called 'trophoblast' (from Greek trephein 'to feed' and blastos 'germinator'). However, in addition to regulating nutrient supply, the placenta also exerts a number of other pivotal functions that highlight the importance of normal trophoblast differentiation for a successful pregnancy. In this guest symposium, 'Trophoblast Development', several contributors summarize insights gained from recent studies in the mouse that have advanced our understanding of trophoblast biology. This includes how the earliest trophoblast cells are set aside to expand in a stem- or progenitor-cell compartment under tight genetic and epigenetic control and how subsequent differentiation into the various placental cell types is controlled to ensure normal placentation. The relevance of these contributions range from early developmental cell fate decisions, stem cell biology and placental development for healthy pregnancy to the impact of placental failures on long-term health, with important clinical implications for assisted reproductive technology procedures and pregnancy-associated complications.