Maternal depression and anxiety are associated with altered gene expression in the human placenta without modification by antidepressant use: implications for fetal programming

Transplacental signals involved in the programming effects of prenatal psychosocial stress on neurodevelopment

Exposure to psychosocial stress during pregnancy has been associated with the emergence of neurodevelopmental and neuropsychiatric disorders in offspring. The placenta is known to orchestrate various functions that are essential for normal fetal development, including the brain. It has therefore been postulated that alterations in such functions, and downstream signaling, have the potential to dramatically affect brain developmental trajectories and contribute to adverse neurodevelopmental outcomes. This review will focus on discussing various placental functions that have been proposed to be affected by exposure to prenatal psychosocial stress and the implications of such disruptions on long-term neurodevelopmental programming.

Causal effects of neuroticism on postpartum depression: a bidirectional mendelian randomization study

PURPOSE

Postpartum depression (PPD) brings adverse and serious consequences to both new parents and newborns. Neuroticism affects PPD, which remains controversial for confounding factors and reverse causality in cross-sectional research. Therefore, mendelian randomization (MR) study has been adopted to investigate their causal relationship.

METHODS

This study utilized large-scale genome-wide association study genetic pooled data from three major databases: the United Kingdom Biobank, the European Bioinformatics Institute, and the FinnGen databases. The causal analysis methods used inverse variance weighting (IVW). The weighted median, MR-Egger method, MR-PRESSO test, and the leave-one-out sensitivity test have been used to examine the results' robustness, heterogeneity, and horizontal pleiotropy. The fixed effect model yielded the results of meta-analysis.

RESULTS

In the IVW model, a meta-analysis of the MR study showed that neuroticism increased the risk of PPD (OR, 1.17; 95% CI, 1.11-1.25, p < 0.01). Reverse analysis showed that PPD could not genetically predict neuroticism. There was no significant heterogeneity or horizontal pleiotropy bias in this result.

CONCLUSION

Our study suggests neuroticism is the risk factor for PPD from a gene perspective and PPD is not the risk factor for neuroticism. This finding may provide new insights into prevention and intervention strategies for PPD according to early detection of neuroticism.

Predicting newborn birth outcomes with prenatal maternal health features and correlates in the United States: a machine learning approach using archival data

BACKGROUND

Newborns are shaped by prenatal maternal experiences. These include a pregnant person's physical health, prior pregnancy experiences, emotion regulation, and socially determined health markers. We used a series of machine learning models to predict markers of fetal growth and development-specifically, newborn birthweight and head circumference (HC).

METHODS

We used a pre-registered archival data analytic approach. These data consisted of maternal and newborn characteristics of 594 maternal-infant dyads in the western U.S. Participants also completed a measure of emotion dysregulation. In total, there were 22 predictors of newborn HC and birthweight. We used regularized regression for predictor selection and linear prediction, followed by nonlinear models if linear models were overfit.

RESULTS

HC was predicted best with a linear model (ridge regression). Newborn sex (male), number of living children, and maternal BMI predicted a larger HC, whereas maternal preeclampsia, number of prior preterm births, and race/ethnicity (Latina) predicted a smaller HC. Birthweight was predicted best with a nonlinear model (support vector machine). Occupational prestige (a marker similar to socioeconomic status) predicted higher birthweight, maternal race/ethnicity (non-White and non-Latina) predicted lower birthweight, and the number of living children, prior preterm births, and difficulty with emotional clarity had nonlinear effects.

CONCLUSIONS

HC and birthweight were predicted by a variety of variables associated with prenatal stressful experiences, spanning medical, psychological, and social markers of health and stress. These findings may highlight the importance of viewing prenatal maternal health across multiple dimensions. Findings also suggest that assessing difficulties with emotional clarity during standard obstetric care (in the U.S.) may help identify risk for adverse newborn outcomes.

Prenatal psychological distress and 11β-HSD2 gene expression in human placentas: Systematic review and meta-analysis

BACKGROUND

The placenta acts as a buffer to regulate the degree of fetal exposure to maternal cortisol through the 11-Beta Hydroxysteroid Dehydrogenase isoenzyme type 2 (11-β HSD2) enzyme. We conducted a systematic review and meta-analysis to assess the effect of prenatal psychological distress (PPD) on placental 11-β HSD2 gene expression and explore the related mechanistic pathways involved in fetal neurodevelopment.

METHODS

We searched PubMed, Embase, Scopus, APA PsycInfo®, and ProQuest Dissertations for observational studies assessing the association between PPD and 11-β HSD2 expression in human placentas. Adjusted regression coefficients (β) and corresponding 95% confidence intervals (CIs) were pooled based on three contextual PPD exposure groups: prenatal depression, anxiety symptoms, and perceived stress.

RESULTS

Of 3159 retrieved records, sixteen longitudinal studies involving 1869 participants across seven countries were included. Overall, exposure to PPD disorders showed weak negative associations with the placental 11-β HSD2 gene expression as follows: prenatal depression (β -0.01, 95% CI 0.05-0.02, I2=0%), anxiety symptoms (β -0.02, 95% CI 0.06-0.01, I2=0%), and perceived stress (β -0.01 95% CI 0.06-0.04, I2=62.8%). Third-trimester PPD exposure was more frequently associated with lower placental 11-β HSD2 levels. PPD and placental 11-β HSD2 were associated with changes in cortisol reactivity and the development of adverse health outcomes in mothers and children. Female-offspring were more vulnerable to PPD exposures.

CONCLUSION

The study presents evidence of a modest role of prenatal psychological distress in regulating placental 11-β HSD2 gene expression. Future prospective cohorts utilizing larger sample sizes or advanced statistical methods to enhance the detection of small effect sizes should be planned. Additionally, controlling for key predictors such as the mother's ethnicity, trimester of PPD exposure, mode of delivery, and infant sex is crucial for valid exploration of PPD effects on fetal programming.

Sex-Specific Transcriptomic Changes in the Villous Tissue of Placentas of Pregnant Women Using a Selective Serotonin Reuptake Inhibitor

About 5% of pregnant women are treated with selective serotonin reuptake inhibitor (SSRI) antidepressants to treat their depression. SSRIs influence serotonin levels, a key factor in neural embryonic development, and their use during pregnancy has been associated with adverse effects on the developing embryo. However, the role of the placenta in transmitting these negative effects is not well understood. In this study, we aim to elucidate how disturbances in the maternal serotonergic system affect the villous tissue of the placenta by assessing whole transcriptomes in the placentas of women with healthy pregnancies and women with depression and treated with the SSRI fluoxetine during pregnancy. Twelve placentas of the Biology, Affect, Stress, Imaging and Cognition in Pregnancy and the Puerperium (BASIC) project were selected for RNA sequencing to examine differentially expressed genes: six male infants and six female infants, equally distributed over women treated with SSRI and without SSRI treatment. Our results show that more genes in the placenta of male infants show changed expression associated with fluoxetine treatment than in placentas of female infants, stressing the importance of sex-specific analyses. In addition, we identified genes related to extracellular matrix organization to be significantly enriched in placentas of male infants born to women treated with fluoxetine. It remains to be established whether the differentially expressed genes that we found to be associated with SSRI treatment are the result of the SSRI treatment itself, the underlying depression, or a combination of the two.

Solid-Phase Microextraction/Gas Chromatography-Time-of-Flight Mass Spectrometry Approach Combined with Network Pharmacology Analysis to Evaluate the Quality of Agarwood from Different Regions against Anxiety Disorder

Agarwood (Aquilaria malaccensis Lam.) is a resinous material from different geographical locations. The current evaluation of agarwood quality is usually based on its physical properties and chemical compounds, yet only a few studies have linked agarwood quality with its anxiolytic effect, as indicated by characteristic compounds. In this study, using solid-phase microextraction/gas chromatography-time-of-flight mass spectrometry (SPME/GC-TOFMS) and multivariate analysis, we found 116 significantly different compounds in agarwood samples from four locations in Southeast Asia with regard to their quality. Brunei and Nha Trang agarwood had abundant sesquiterpenoids, exhibiting notable pharmacological efficacy in relieving anxiety. Malaysian and Irian agarwood had abundant alcohols and aldehydes, qualifying them as high-quality spices. Compound-target-disease network and pathway enrichment analysis were further employed to predict 79 gene targets and 20 pathways associated with the anxiolytic effects based on the 62 sesquiterpenoids. The correlated relationships among the sesquiterpenoids and targets suggest that agarwood treats anxiety via multiple compounds acting on multiple targets. Varying levels of sesquiterpenes across agarwood groups might lead to differences in the anxiolytic effects via signaling pathways, such as neurotransmitter- and hormone-regulated pathways. Our study originally evaluates agarwood quality and its anxiolytic effect by linking the characteristic compounds to potential gene targets and pathways.

DNA methylation in former extremely low birth weight newborns: association with cardiovascular and endocrine function

BACKGROUND

There is increased risk of cardiovascular, metabolic, and hypertensive disorders in later life in the preterm population. We studied school-age children who had been born extremely premature who had undergone endocrine, cardiovascular, and anthropometric evaluations.

METHODS

School age measurements of salivary cortisol, adrenal androgens, blood pressure, and anthropometric markers were correlated with DNA methylation of 11-betahydroxysteroid dehydrogenase type 2 (11BHSD2), leptin, and the LINE1 repetitive DNA element.

RESULTS

We observed a modest correlation between log AUC for salivary cortisol and methylation of leptin in preterm infants and a negative correlation between methylation of region 1 of the glucocorticoid receptor (GR in term-born infants. There was an association between LINE1 methylation and cortisol response to awakening and a negative correlation between LINE1 and systolic blood pressure at 6-7 years. Methylation of the GR promoter region showed a positive association with systolic blood pressure at 6-7 years of age.

CONCLUSIONS

These results show that extremely preterm birth, followed by complex patterns of endocrine, cardiovascular, and metabolic exposures during early postnatal life, is associated with lasting changes in DNA methylation patterns in genes involved in hypothalamic pituitary adrenal axis function, adrenal hormonal regulation, and cardiometabolic risk.

IMPACT

Preterm infants have significant environmental and physiological exposures during early life that may have lasting impact on later function. Alterations in hypothalamic pituitary adrenal axis (HPA) function have been associated with these exposures. We examined the associated changes in DNA methylation of important genes involved in HPA function, metabolism, and global DNA methylation. The changes we saw in DNA methylation may help to explain associated cardiovascular, metabolic, and growth disturbance in these children in later life.

Gestational Age Variation in Human Placental Drug Transporters

Patient and providers’ fear of fetal exposure to medications may lead to discontinuation of treatment, disease relapse, and maternal morbidity. Placental drug transporters play a critical role in fetal exposure through active transport but the majority of data are limited to the 3rd trimester, when the majority of organogenesis has already occurred. Our objective was to define gestational age (GA) dependent changes in protein activity, expression and modifications of five major placental drug transporters: SERT, P-gp, NET, BCRP and MRP3. Apical brush border membrane fractions were prepared from fresh 1st, 2nd and 3rd trimester human placentas collected following elective pregnancy termination or planned cesarean delivery. A structured maternal questionnaire was used to identify maternal drug use and exclude exposed subjects. Changes in placental transporter activity and expression relative to housekeeping proteins were quantified. There was evidence for strong developmental regulation of SERT, NET, P-gp, BCRP and MRP3. P-gp and BCRP decreased with gestation (r = −0.72, p &lt; 0.001 and r = −0.77, p &lt; 0.001, respectively). Total SERT increased with gestation but this increase was due to a decrease in SERT cleavage products across trimesters. Uncleaved SERT increased with GA (r = 0.89, p &lt; 0.001) while cleaved SERT decreased with GA (r = −0.94, p &lt; 0.001). Apical membrane NET overall did not appear to be developmentally regulated (r = −0.08, p = 0.53). Two forms of MRP3 were identified; the 50 kD form did not change across GA; the 160 kD form was steady in the 1st and 2nd trimester and increased in the 3rd trimester (r = 0.24, p = 0.02). The 50 kD form was expressed at higher levels. The observed patterns of SERT, NET P-gp, BCRP and MRP3 expression and activity may be associated with transporter activity or decreased placental permeability in the 1st trimester to transporter specific substrates including commonly used psychoactive medications such as anti-depressants, anti-psychotics, and amphetamines, while transport of nutrients and serotonin is important in the 1st trimester. Overall these observations are consistent with a strong protective effect during organogenesis. 3rd trimester estimates of fetal exposure obtained from cord blood likely significantly overestimate early fetal exposure to these medications at any fixed maternal dose.

Perinatal Maternal Mental Health and Breastfeeding Are Associated with Infant and Toddler Sensory Profiles

Infants’ sensory processing may impact their development and daily functioning in multiple domains, as does the mental health of their mothers. Little research has been conducted exploring the novel construct of sensory processing in relation to maternal mental health and arguably one of the most important co-occupations during this sensitive time (i.e., breastfeeding), which may also be impacted by maternal mental health. Therefore, this study aims to explore associations between maternal mental health, the co-occupation of breastfeeding, and the sensory processing profiles of infants. Specifically, a sample of maternal-offspring dyads was examined from pre-gestation through the infant’s age of 18 months. Mothers completed well-validated and contemporary self-report questionnaires of mental health (i.e., depression and anxiety symptom severity) and sensory processing across time points. Findings yielded statistically significant relationships between maternal prenatal and postnatal anxiety and depression symptom severity and infants’ sensory processing profiles. Further connections were found between infants’ sensory processing profiles and both duration and frequency of breastfeeding. The study provides health care professionals with additional perspectives on how maternal mental health status and breastfeeding may be related to infants’ sensory processing profiles.

Fetal programming pathway from maternal mental health to infant cortisol functioning: The role of placental 11β-HSD2 mRNA expression

Placental 11β-HSD2 has been a focus of research for understanding potential fetal programming associated with maternal emotional disorders. This study examined the pathway from antenatal mental health via placental 11β-HSD2 mRNA to cortisol regulation in the infant offspring. This study reports on data obtained from 236 participants in the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS). At term, placental tissue was collected within 30 min of birth from 52 participants meeting current criteria for a depressive disorder, and 184 control participants. Depressive disorders were diagnosed using the SCID-IV. In addition, antidepressant use, depressive and anxiety symptoms were measured in early and late pregnancy. Placental 11β-HSD2 mRNA expression was measured using qRT-PCR. Infant salivary cortisol samples were taken at 12 months of age. Women on antidepressant medication and with higher trait anxiety had higher placental 11β-HSD2 expression compared to women not taking medication. Furthermore, the offspring of women taking an antidepressant and who also had a current depressive disorder and high trait anxiety had high cortisol reactivity at 12 months of age and this was mediated through 11β-HSD2 mRNA expression. In contrast, offspring of women not taking antidepressant medication with depressive disorder and high anxiety there was low cortisol reactivity observed. Our findings suggest that the relationship between maternal antenatal depression and anxiety and infant cortisol reactivity is mediated through placental 11β-HSD2 mRNA expression. Furthermore, the direction differed for women taking antidepressants, where infant cortisol reactivity was high whereas when compared to those with unmedicated depression and anxiety, where infant cortisol reactivity was low.

The role of epigenetics in perinatal depression: Are there any candidate biomarkers?

BACKGROUND

Approximately 12% of all women will be affected by Perinatal Depression (PD), a condition associated with an increased risk for low birth weight, preterm birth, preeclampsia, maternal suicide and infanticide. The identification of biomarkers for PD could be useful for early identification and for the development of new treatments. Purpose of the present manuscript is to review the potential epigenetic biomarkers which were associated with PD.

METHODS

We performed a bibliographic research on PubMed, in order to find studies that proposed epigenetic biomarkers for PD. A total of 9 studies met our inclusion criteria.

RESULTS

Most available data are concordant in showing that women affected by PD have epigenetic alterations versus Healthy Controls (HC), especially with regard to Hypothalamic Pituitary Adrenal (HPA) axis, oxytocin system, inflammatory response, neuronal differentiation and circadian rhythms. PD might be characterized by specific epigenetic changes; however, the available data are preliminary.

LIMITATIONS

Many articles report results obtained on a limited sample size, in different cell types or tissues. Furthermore, sometimes the studies selected a restricted number of genes. As a result, most available data have not been replicated.

CONCLUSIONS

Epigenetic changes of different biological systems could be involved in the etiology of PD. However, until now data are too scanty to draw definitive conclusions. Future studies with larger samples can confirm the results and hypothesis presented in this review.

Antenatal and Postnatal Maternal Depressive Symptoms and Trajectories and Child Hospitalization up to 24 Months of Life: Findings From the 2015 Pelotas (Brazil) Birth Cohort Study

Objective

To examine the association between antenatal and postnatal maternal depression symptoms, and child hospitalization during the first 2 years of life in the 2015 Pelotas Birth Cohort Study.

Study design

This is an observational study. Maternal depressive symptoms of 4275 mothers were measured using the Edinburgh Postnatal Depression Scale. Hospitalization of the child for any reason was assessed using maternal report. Bivariate analysis and multivariate Poisson regressions were used to assess the association between maternal depressive symptoms and child hospitalization.

Results

Compared with children of mothers with low depressive symptoms, children whose mothers experienced significant antenatal depressive symptoms were 1.74 (95% CI, 1.16-2.60) times more likely to be hospitalized by 3 months of age, and 2.14 (95% CI, 1.46-3.14) times more likely up to 24 months. For children whose mothers experienced severe postnatal depressive symptoms at 3 months, the risks for hospitalization by age 12 months were 1.84 (95% CI, 1.39-2.45) higher than children whose mothers had low depressive symptoms. There was an increased risk of hospitalization for children according to the severity of depressive trajectories across time.

Conclusions

Maternal depressive symptoms are a risk factor for hospitalization in children up to 2 years of age, and this risk increases with increased severity of depression. These results have public health relevance for decreasing the risk factors in mothers that can lead to hospitalization in children.

Maternal antioxidant treatment prevents the adverse effects of prenatal stress on the offspring's brain and behavior

Maternal exposure to stress during pregnancy is associated with an increased risk of psychiatric disorders in the offspring in later life. The mechanisms through which the effects of maternal stress are transmitted to the fetus are unclear, however the placenta, as the interface between mother and fetus, is likely to play a key role. Using a rat model, we investigated a role for placental oxidative stress in conveying the effects of maternal social stress to the fetus and the potential for treatment using a nanoparticle-bound antioxidant to prevent adverse outcomes in the offspring.

Maternal psychosocial stress increased circulating corticosterone in the mother, but not in the fetuses. Maternal stress also induced oxidative stress in the placenta, but not in the fetal brain. Blocking oxidative stress using an antioxidant prevented the prenatal stress-induced anxiety phenotype in the male offspring, and prevented sex-specific neurobiological changes, specifically a reduction in dendrite lengths in the hippocampus, as well as reductions in the number of parvalbumin-positive neurons and GABA receptor subunits in the hippocampus and basolateral amygdala of the male offspring. Importantly, many of these effects were mimicked in neuronal cultures by application of placental-conditioned medium or fetal plasma from stressed pregnancies, indicating molecules released from the placenta may mediate the effects of prenatal stress on the fetal brain. Indeed, both placenta-conditioned medium and fetal plasma contained differentially abundant microRNAs following maternal stress, and their predicted targets were enriched for genes relevant to nervous system development and psychiatric disorders.

The results highlight placental oxidative stress as a key mediator in transmitting the maternal social stress effects on the offspring's brain and behavior, and offer a potential intervention to prevent stress-induced fetal programming of affective disorders.

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Social stress in pregnancy induces oxidative stress but is prevented by antioxidant.

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Prenatal stress induces behavioural, neuroanatomical and neurochemical changes.

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Maternal antioxidant treatment prevents stress-induced effects in the offspring.

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Maternal stress alters the balance of microRNAs secreted from the placenta.

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Placental oxidative stress mediates maternal social stress effects on the offspring.

The effects of pre- and post-partum depression on child behavior and psychological development from birth to pre-school age: a protocol for a systematic review and meta-analysis

BACKGROUND

Pre- and post-partum depression is a common mood disorder with detrimental effects on both mother and child. The aim of the proposed review is to summarize evidence related to the effects of both pre- and post-partum depression on child behavior and development from birth to preschool age. In particular, our review will address mutual relations between pre- and post-partum depression in order to determine whether pre- and post-partum depression predict child psychological outcomes independently, whether there is an effect of timing of depression on child outcomes, whether pre- and post-partum depression interact to affect child outcomes, and whether the effect of pre-partum depression is mediated by depression after child's birth.

METHODS

We will include prospective longitudinal studies that report data about the effects of both pre- and post-partum depression on child psychological outcomes as published in peer-reviewed academic journals since January 1998. We will search EMBASE, MEDLINE, PsycARTICLES, PsycINFO, ISI Web of Science, Scopus, and Wiley Online databases to identify original research articles written in English. Two independent reviewers will screen search results in two stages: (i) titles and abstracts and (ii) full text. The first one will extract data into tables, while the latter will verify whether the data extracted are correct. We will assess the risk of bias in the selected studies using the Critical Appraisal Skills Programme (CASP), Cohort Study Checklist. The results of the review will be reported in a narrative form. If there are sufficient data available, a meta-analysis will be conducted using metaSEM package in R.

DISCUSSION

The proposed review will be the first systematic review summarizing the effects of both pre- and post-partum depression on child psychological development and behavior from birth to preschool age. The results of such a review may contribute to a better understanding of mutual relations between pre- and post-partum depression in their effects on child outcomes. They may also shed light on what periods in early human development are most vulnerable to the effects of maternal depression.

TRIAL REGISTRATION

PROSPERO CRD42018106269.

Maternal stress in relation to sex-specific expression of placental genes involved in nutrient transport, oxygen tension, immune response, and the glucocorticoid barrier

INTRODUCTION

Murine models provide evidence that maternal stress during pregnancy can influence placenta morphology and function, including altered expression of genes involved in the maintenance and progression of pregnancy and fetal development. Corresponding research evaluating the impact of maternal stress on placental gene expression in humans is limited. We examined maternal stress in relation to placental expression of 17 candidate genes in a community-based sample.

METHODS

Participants included 60 mother-newborn pairs enrolled in the PRogramming of Intergenerational Stress Mechanisms pregnancy cohort based at the Mount Sinai Hospital in New York City. Placentas were collected immediately following delivery and gene expression was measured using a qPCR-based platform. Maternal experiences of traumatic and non-traumatic stress were measured using the Life Stressor Checklist-Revised (LSC-R) administered during a mid-pregnancy interview. We used multivariable linear regression to examine associations between LSC-R scores and expression of each gene in separate models in the sample overall and stratified by fetal sex.

RESULTS

Higher maternal stress was associated with significantly increased placental expression of the nutrient sensor gene OGT, the glucose transporter gene GLUT1, and the hypoxia sensor gene HIF3A. In models stratified by fetal sex, significant associations remained only among males.

DISCUSSION

This study represents one of the most comprehensive examinations of maternal lifetime traumatic and non-traumatic stress in relation to placental gene expression in human tissue. Our findings support that maternal stress may alter sex-specific placental expression of genes involved in critical developmental processes.

Placental Gene Expression and Offspring Temperament Trajectories: Predicting Negative Affect in Early Childhood

Exposure to prenatal stress increases offspring risk for long-term neurobehavioral impairments and psychopathology, such as Attention Deficit Hyperactivity Disorder (ADHD). Epigenetic regulation of glucocorticoid pathway genes may be a potential underlying mechanism by which maternal conditions 'program' the fetal brain for downstream vulnerabilities. The present study aims to investigate whether mRNA expression of glucocorticoid pathway genes in the placenta predict offspring negative affect during early childhood (between 6 and 24 months). Participants include 318 mother-child dyads participating in a longitudinal birth cohort study. Placental mRNA expression of glucocorticoid pathway genes (HSD11B1, HSD11B2, NR3C1, NCOR2) were profiled and negative affect traits of the offspring were measured at 6, 12, 18, and 24 months. HSD11B1 mRNA expression significantly predicted negative affect (β = -.09, SE = .04; p = .036), and Distress to Limitations trajectories (β = -.13, SE = .06; p = .016). NCOR2 mRNA expression significantly predicted Distress to Limitations (β = .43, SE = .21; p = .047), and marginally predicted Sadness trajectories (β = .39, SE = .21; p = .068). HSD11B2 and NR3C1 did not predict trajectories of Negative Affect or subscale scores. Infant negative affect traits were assessed via maternal self-report, and deviated from linearity across follow-up. mRNA expression of glucocorticoid pathway genes in the placenta may be a potentially novel tool for early identification of infants at greater risk for elevated negative affect. Further study is needed to validate the utility of mRNA expression of glucocorticoid pathway genes in the placenta.

Moderate prenatal stress may buffer the impact of Superstorm Sandy on placental genes: Stress in Pregnancy (SIP) Study

The placenta plays a central role in the epigenetic programming of neurodevelopment by prenatal stress (PS), but this pathway is not fully understood. It difficult to study in humans because the conditions for intense, traumatic PS are almost impossible to create ethically. This study was able to capitalize on a 2012 disaster that hit New York, Superstorm Sandy, to examine the impact of traumatic stress on placental gene expression while also examining normative PS, and compare the two. Of the 303 expectant mothers participating in the Stress in Pregnancy Study, 95 women were pregnant when Superstorm Sandy struck. During their pregnancy, participants completed self-report measures of PS and distress that were combined, using latent profile analysis, into one global indicator of normative PS. Placental tissue was collected at delivery and frozen for storage. RNA expression was assessed for 40 placental genes known to associate with the stress response system and neurodevelopment in offspring. Results showed that normative PS increased expression of just MECP2, HSD11B2, and ZNF507, whereas Superstorm Sandy PS decreased expression of CDKL5, CFL1, DYRK1A, HSD11B2, MAOA, MAOB, NCOR1, and ZNF507. Interaction analyses indicated that Superstorm Sandy PS was associated with decreased gene expression for the low and high PS group for CFL1, DYRK1A, HSD11B2, MAOA, and NCOR1 and increased expression for the moderate PS group for FOXP1, NR3C1, and NR3C2. This study supports the idea that a moderate amount of normative PS may buffer the impact of traumatic PS, in this case caused by Superstorm Sandy, on placental gene expression, which suggests that the placenta itself mirrors the organism's ability to develop an epigenetic resilience to, and inoculation from, stress.

The effect of antenatal depression and antidepressant treatment on placental tissue: a protein-validated gene expression study

Background

Antenatal depression affects 10–20% of pregnant women. Around 2–4% of European pregnant women use antidepressant treatment, most commonly selective serotonin reuptake inhibitors (SSRIs). Poor pregnancy outcomes, such as preterm birth and low birth weight, have been described in women with antenatal depression and in pregnant women on SSRI treatment. However, the effects of antenatal depression and antidepressant treatment on the placenta are largely unknown. The aim of this work was to compare placental gene and protein expression in healthy women, women with untreated antenatal depression and women on antidepressant treatment during pregnancy.

Methods

Placental samples from 47 controls, 25 depressed and 45 SSRI-treated women were analysed by means of qPCR using custom-designed TaqMan low-density arrays (TLDAs) for 44 genes previously known to be involved in the pathophysiology of depression, and expressed in the placenta. Moreover, placental protein expression was determined by means of immunohistochemistry in 37 healthy controls, 13 women with untreated depression and 21 women on antidepressant treatment. Statistical comparisons between groups were performed by one-way ANOVA or the Kruskal–Wallis test.

Results

Nominally significant findings were noted for HTR1A and NPY2R, where women with untreated depression displayed higher gene expression than healthy controls (p < 0.05), whereas women on antidepressant treatment had similar expression as healthy controls. The protein expression analyses revealed higher expression of HTR1A in placentas from women on antidepressant treatment, than in placentas from healthy controls (p < 0.05).

Conclusion

The differentially expressed HTR1A, both at the gene and the protein level that was revealed in this study, suggests the involvement of HTR1A in the effect of antenatal depression on biological mechanisms in the placenta. More research is needed to elucidate the role of depression and antidepressant treatment on the placenta, and, further, the effect on the fetus.

Cellular stress mechanisms of prenatal maternal stress: Heat shock factors and oxidative stress

Development of the brain prenatally is affected by maternal experience and exposure. Prenatal maternal psychological stress changes brain development and results in increased risk for neuropsychiatric disorders. In this review, multiple levels of prenatal stress mechanisms (offspring brain, placenta, and maternal physiology) are discussed and their intersection with cellular stress mechanisms explicated. Heat shock factors and oxidative stress are closely related to each other and converge with the inflammation, hormones, and cellular development that have been more deeply explored as the basis of prenatal stress risk. Increasing evidence implicates cellular stress mechanisms in neuropsychiatric disorders associated with prenatal stress including affective disorders, schizophrenia, and child-onset psychiatric disorders. Heat shock factors and oxidative stress also have links with the mechanisms involved in other kinds of prenatal stress including external exposures such as environmental toxicants and internal disruptions such as preeclampsia. Integrative understanding of developmental neurobiology with these cellular and physiological mechanisms is necessary to reduce risks and promote healthy brain development.

Effect of prematurity on genome wide methylation in the placenta

Background

Preterm birth is a significant clinical problem and an enormous burden on society, affecting one in eight pregnant women and their newborns. Despite decades of research, the molecular mechanism underlying its pathogenesis remains unclear. Many studies have shown that preterm birth is associated with health risks across the later life course. The “fetal origins” hypothesis postulates that adverse intrauterine exposures are associated with later disease susceptibility. Our recent studies have focused on the placental epigenome at term. We extended these studies to genome-wide placental DNA methylation across a wide range of gestational ages. We applied methylation dependent immunoprecipitation/DNA sequencing (MeDIP-seq) to 9 placentas with gestational age from 25 weeks to term to identify differentially methylated regions (DMRs).

Results

Enrichment analysis revealed 427 DMRs with nominally significant differences in methylation between preterm and term placentas (p < 0.01) and 21 statistically significant DMRs after multiple comparison correction (FDR p < 0.05), of which 62% were hypo-methylated in preterm placentas vs term placentas. The majority of DMRs were in distal intergenic regions and introns. Significantly enriched pathways identified by Ingenuity Pathway Analysis (IPA) included Citrulline-Nitric Oxide Cycle and Fcy Receptor Mediated Phagocytosis in macrophages. The DMR gene set overlapped placental gene expression data, genes and pathways associated evolutionarily with preterm birth.

Conclusion

These studies form the basis for future studies on the epigenetics of preterm birth, “fetal programming” and the impact of environment exposures on this important clinical challenge.

Electronic supplementary material

The online version of this article (10.1186/s12881-019-0835-6) contains supplementary material, which is available to authorized users.

The Relationship Between Pregnancy Exposure to Antidepressant and Atypical Antipsychotic Medications and Placental Weight and Birth Weight Ratio: A Retrospective Cohort Study

BACKGROUND

Psychotropic medication use in pregnancy has been associated with altered fetal growth. The aim of this study was to investigate the relationship between placental weight and placental weight-to-birth weight (PBW) ratio, as a potential marker of placental efficiency, and medication use in a cohort of women with severe mental illness in pregnancy.

METHODS

A retrospective database analysis was carried out on a cohort of pregnant women with severe mental illness (242 singleton pregnancies) and grouped according to their psychotropic medication use. Demographic, obstetric, neonatal, and psychiatric variables were analyzed using t tests, χ, analysis of variance, univariate, binary, and multiple regression adjusting for potential confounders.

RESULTS

Multiple regression analysis demonstrated a mean adjusted increase in placental weight of 114 g (95% confidence interval [CI], 60.2-165.6 g) in women taking antidepressant medication and 113 g (CI, 65.1-162.8 g) in women taking combined antidepressant and atypical antipsychotic medication in pregnancy. There was also a significantly elevated PBW ratio in these 2 medication groups (B 0.02: CI, 0.006-0.034; and B 0.025: CI, 0.012-0.038). Binary regression, adjusted for sex and gestational age, showed a significant odds ratio of 4.57 (95% CI, 2.17-9.62) for PBW ratio of greater than 90% in those taking antidepressant medication, either alone or in combination, compared with unmedicated women.

CONCLUSIONS

The use of antidepressant medication, alone or in combination, has a significant effect on placental weight and PBW ratio after adjusting for confounding variables. Given that this may reflect adverse effects on intrauterine growth and have possible long-term implications for the fetus, further research is warranted to confirm these findings.

Behavioural dysfunctions of 10-year-old children born extremely preterm associated with corticotropin-releasing hormone expression in the placenta

AIM

To evaluate the relationship between corticotropin-releasing hormone (CRH) expression in the placenta and the risk of school-related dysfunctions at the age of 10 years among children born extremely preterm (EP).

METHODS

Corticotropin-releasing hormone expression was measured in the placenta of 761 EP children, who had the following assessments at the age of 10 years: Differential Ability Scales, Oral and Written Language Scales, the Wechsler Individual Achievement Test-III, NEPSY-II and the Child Symptom Inventory-4. We evaluated whether lowest and highest quartiles of CRH mRNA were associated with undesirable scores on these assessments. With 272 evaluations, we would expect 14 to be significant at p < 0.05.

RESULTS

Only 16 associations were statistically significant. On the other hand, seven of these were social limitations among girls whose placenta CRH mRNA was in the top quartile. Adjusting for delivery indication or restricting the sample to one delivery indication group resulted in few differences.

CONCLUSION

Overall, placenta CRH mRNA concentrations in the top or bottom quartiles were not associated with increased risks of dysfunctions 10 years later. Girls whose placenta CRH expression was in the top quartile, however, were at increased risk of seven indicators/correlates of social limitations.

Prenatal programming of postnatal plasticity revisited-And extended

Two sets of evidence reviewed herein, one indicating that prenatal stress is associated with elevated behavioral and physiological dysregulation and the other that such phenotypic functioning is itself associated with heightened susceptibility to positive and negative environmental influences postnatally, raises the intriguing hypothesis first advanced by Pluess and Belsky (2011) that prenatal stress fosters, promotes, or "programs" postnatal developmental plasticity. Here we review further evidence consistent with this proposition, including new experimental research systematically manipulating both prenatal stress and postnatal rearing. Collectively this work would seem to explain why prenatal stress has so consistently been linked to problematic development: stresses encountered prenatally are likely to continue postnatally, thereby adversely affecting the development of children programmed (by prenatal stress) to be especially susceptible to environmental effects. Less investigated are the potential benefits prenatal stress may promote, due to increased plasticity, when the postnatal environment proves to be favorable. Future directions of research pertaining to potential mechanisms instantiating postnatal plasticity and moderators of such prenatal-programming effects are outlined.

Epigenetic Inheritance: Concepts, Mechanisms and Perspectives

Parents’ stressful experiences can influence an offspring’s vulnerability to many pathological conditions, including psychopathologies, and their effects may even endure for several generations. Nevertheless, the cause of this phenomenon has not been determined, and only recently have scientists turned to epigenetics to answer this question. There is extensive literature on epigenetics, but no consensus exists with regard to how and what can (and must) be considered to study and define epigenetics processes and their inheritance. In this work, we aimed to clarify and systematize these concepts. To this end, we analyzed the dynamics of epigenetic changes over time in detail and defined three types of epigenetics: a direct form of epigenetics (DE) and two indirect epigenetic processes—within (WIE) and across (AIE). DE refers to changes that occur in the lifespan of an individual, due to direct experiences with his environment. WIE concerns changes that occur inside of the womb, due to events during gestation. Finally, AIE defines changes that affect the individual’s predecessors (parents, grandparents, etc.), due to events that occur even long before conception and that are somehow (e.g., through gametes, the intrauterine environment setting) transmitted across generations. This distinction allows us to organize the main body of epigenetic evidence according to these categories and then focus on the latter (AIE), referring to it as a faster route of informational transmission across generations—compared with genetic inheritance—that guides human evolution in a Lamarckian (i.e., experience-dependent) manner. Of the molecular processes that are implicated in this phenomenon, well-known (methylation) and novel (non-coding RNA, ncRNA) regulatory mechanisms are converging. Our discussion of the chief methods that are used to study epigenetic inheritance highlights the most compelling technical and theoretical problems of this discipline. Experimental suggestions to expand this field are provided, and their practical and ethical implications are discussed extensively.

Prenatal stress and enhanced developmental plasticity

Two separate lines of inquiry indicate (a) that prenatal stress is associated with heightened behavioral and physiological reactivity, and (b) that these postnatal phenotypes are associated with increased susceptibility to both positive and negative developmental experiences and environmental exposures. This research considered together raises the intriguing hypothesis first advanced by Pluess and Belsky (Dev Psychopathol 23:29-38, 2011) that prenatal-stress fosters, promotes or "programs" postnatal developmental plasticity. In this paper, we review further evidence consistent with this proposition, including a novel animal study which experimentally manipulated both prenatal stress and postnatal rearing. Directions for future work focused on mechanisms mediating the plasticity-inducing effects of prenatal stress and the moderators of such effects are outlined.

Natural disaster-related prenatal maternal stress is associated with alterations in placental glucocorticoid system: The QF2011 Queensland Flood Study

We investigated the effects of a natural disaster (a sudden flood) as a source of prenatal maternal stress (PNMS) on the placental glucocorticoid system and glucose transporters. Whether the gestational age at the time of the flood moderated these effects was also evaluated. Placental samples were collected from participants in the 2011 Queensland Flood Study (QF2011) who were pregnant in the first or second trimester at the onset of the flood. Detailed questionnaire results for objective hardship and composite subjective distress were obtained to assess stress levels. Subjective distress was significantly associated with a reduction in placental NR3C1-β mRNA levels for males only (β = -0.491, p = 0.005). In female placentas, objective hardship was marginally linked with lower SLC2A1 mRNA levels while subjective distress was a marginally significant predictor of higher placental SLC2A4 mRNA levels. Gestational age at the time of the flood was a significant moderator of the effect of subjective distress on placental mRNA levels for NR3C1-α (p = 0.046) and HSD11B1 (p = 0.049) in male placentas: if the flood occurred in mid-pregnancy, lower subjective distress predicted higher HSD11B1 while higher subjective distress predicted lower NR3C1-α placental mRNA level. While results did not show any PNMS effects on placental HSD11B2 mRNA and protein levels, and activity, we showed a reduction in placental NR3C1-β mRNA level in male placentas. Our results show evidence of distinct placental glucocorticoid and glucose systems adaptations to PNMS as a function of fetal sex and gestational timing of exposure, with high subjective PNMS in mid-pregnancy associated with lower levels of expression of glucocorticoid-promoting gene in males, leaving the fetus less protected against maternal stress. The exact mechanism by which natural disaster-related PNMS acts on the placenta and the impact on fetal programming requires further investigation.

Maternal depression and cortisol in pregnancy predict offspring emotional reactivity in the preschool period

Prenatal exposures to higher levels of maternal cortisol and depression have been linked to a variety of adverse physiological, neurological, and behavioral outcomes, such as dysregulated cortisol production, structural and functional differences in limbic areas of the brain, and greater negative emotionality. This study investigated prospective associations between maternal prepartum depression/cortisol levels and offspring emotional reactivity in 163 mother-child pairs. Women were assessed repeatedly during pregnancy, and later participated in a laboratory visit with their preschool-aged children. Mothers self-reported on depressive symptomatology during pregnancy and provided saliva samples for cortisol assay. Offspring emotional reactivity was assessed through multiple measures, including caregiver reports, cortisol response following a stressor, and laboratory observations of behavior. The findings suggest potential prenatal timing effects, with depression and maternal cortisol measured in the first and second trimesters being more strongly associated with child emotional reactivity. Sex was found to moderate associations between maternal prepartum depression/cortisol and child emotional reactivity, with the general pattern reflecting positive associations in girls, and negative associations in boys.

Timing of prenatal exposure to trauma and altered placental expressions of hypothalamic-pituitary-adrenal axis genes and genes driving neurodevelopment

Prenatal maternal stress increases the risk for negative developmental outcomes in offspring; however, the underlying biological mechanisms remain largely unexplored. In the present study, alterations in placental gene expression associated with maternal stress were examined to clarify the potential underlying epi/genetic mechanisms. Expression levels of 40 selected genes involved in regulating foetal hypothalamic-pituitary-adrenal axis and neurodevelopment were profiled in placental tissues collected from a birth cohort established around the time of Superstorm Sandy. Objective prenatal traumatic stress was defined as whether mothers were exposed to Superstorm Sandy during pregnancy. Among the 275 mother-infant dyads, 181 dyads were delivered before Superstorm Sandy (ie, Control), 66 dyads were exposed to Superstorm Sandy during the first trimester (ie, Early Exposure) and 28 were exposed to Superstorm Sandy during the second or third trimester (ie, Mid-Late Exposure). Across all trimesters, expression of HSD11B2, MAOA, ZNF507 and DYRK1A was down-regulated among those exposed to Superstorm Sandy during pregnancy. Furthermore, trimester-specific differences were also observed: exposure during early gestation was associated with down-regulation of HSD11B1 and MAOB and up-regulation of CRHBP; exposure during mid-late gestation was associated with up-regulation of SRD5A3. The findings of the present study suggest that placental gene expression may be altered in response to traumatic stress exposure during pregnancy, and the susceptibility of these genes is dependent on the time of the exposure during pregnancy. Further studies should aim to clarify the biological mechanisms that underlie trimester-specific exposure by evaluating the differential impact on offspring neurodevelopment later in childhood.

Maternal depression, antidepressant use and placental oxytocin receptor DNA methylation: Findings from the MPEWS study

The aim of this study was to investigate placental DNA methylation of the oxytocin receptor gene (OXTR) in women with depression in pregnancy. We also explored the role of antidepressant medication in pregnancy on placental OXTR methylation. Data were obtained from 239 women in the Mercy Pregnancy and Emotional Wellbeing Study (MPEWS), a selected pregnancy cohort. Current depressive disorders were diagnosed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (SCID-IV). Depressive symptoms were measured during the third trimester in pregnancy using the Edinburgh Postnatal Depression Scale (EPDS). Plasma levels of antidepressant drugs were measured in maternal and cord blood obtained at delivery. OXTR DNA methylation was measured in placenta samples. Depressive symptoms in pregnancy were not associated with significant changes in DNA methylation of OXTR in the placenta. Cord plasma antidepressant levels were more strongly associated than maternal antidepressant dose or circulating blood antidepressant levels with increased DNA methylation of a specific unit within the promotor region of OXTR. This study provides preliminary data to suggest that antidepressant use during pregnancy can alter OXTR methylation in placental tissue. Our findings also indicate that the way exposures are measured in pregnancy can influence the direction and strength of findings. Future studies should investigate whether altered OXTR methylation might mediate the impacts of maternal antidepressant treatment on pregnancy and offspring outcomes.

Early-life adversity and long-term neurobehavioral outcomes: epigenome as a bridge?

Accumulating evidence suggests that adversities at critical periods in early life, both pre- and postnatal, can lead to neuroendocrine perturbations, including hypothalamic-pituitary-adrenal axis dysregulation and inflammation persisting up to adulthood. This process, commonly referred to as biological embedding, may cause abnormal cognitive and behavioral functioning, including impaired learning, memory, and depressive- and anxiety-like behaviors, as well as neuropsychiatric outcomes in later life. Currently, the regulation of gene activity by epigenetic mechanisms is suggested to be a key player in mediating the link between adverse early-life events and adult neurobehavioral outcomes. Role of particular genes, including those encoding glucocorticoid receptor, brain-derived neurotrophic factor, as well as arginine vasopressin and corticotropin-releasing factor, has been demonstrated in triggering early adversity-associated pathological conditions. This review is focused on the results from human studies highlighting the causal role of epigenetic mechanisms in mediating the link between the adversity during early development, from prenatal stages through infancy, and adult neuropsychiatric outcomes. The modulation of epigenetic pathways involved in biological embedding may provide promising direction toward novel therapeutic strategies against neurological and cognitive dysfunctions in adult life.

Prenatal Depression and Infant Temperament: The Moderating Role of Placental Gene Expression

Prior research has demonstrated the link between maternal depression during pregnancy (i.e., prenatal depression) and increased neurodevelopmental dysregulation in offspring. However, little is known about the roles of key hypothalamic-pituitary axis regulatory genes in the placenta modulating this association. This study will examine whether placental gene expression levels of 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2), glucocorticoid receptor (NR3C1), and mineralocorticoid receptor (NR3C2) can help elucidate the underlying mechanisms linking prenatal depression to infant temperament, particularly in infants with high negativity and low emotion regulation. Stored placenta tissues (N = 153) were used to quantify messenger ribonucleic acid levels of HSD11B2, NR3C1, and NR3C2. Assessments of prenatal depression and infant temperament at 6 months of age were ascertained via maternal report. Results found that prenatal depression was associated with increased Negative Affectivity (p < .05) after controlling for postnatal depression and psychosocial characteristics. Furthermore, the association between prenatal depression and Negative Affectivity was moderated by gene expression levels of HSD11B2, NR3C1, and NR3C2 such that greater gene expression significantly lessened the association between prenatal depression and Negative Affectivity. Our findings suggest that individual differences in placental gene expression may be used as an early marker of susceptibility or resilience to prenatal adversity.

Prenatal Major Depressive Disorder, Placenta Glucocorticoid and Serotonergic Signaling, and Infant Cortisol Response

OBJECTIVES

Extending prior studies of prenatal adversity and depressive symptoms, we tested associations between maternal prenatal major depressive disorder (MDD) and infant cortisol regulation. Based on prior findings by our group, we also tested placenta glucocorticoid (HSD11B2 methylation) and serotonin (SLC6A4 gene expression) signaling as moderators of links between prenatal MDD and infant cortisol.

METHODS

Participants were 153 mother-infant pairs from a low-income, diverse sample (M [SD] age = 26 [6] years). Repeated structured diagnostic interviews were used to identify mothers with (a) prenatal MDD, (b) preconception-only MDD, and (c) controls. Placenta samples were assayed for HSD11B2 methylation and SLC6A4 gene expression. Infant salivary cortisol response to a neurobehavioral examination was assessed at 1 month.

RESULTS

Daughters of prenatal MDD mothers had 51% higher baseline (ratio = 1.51; 95% confidence interval [CI] = 1.01-2.27; p = .045) and 64% higher stress responsive cortisol (ratio = 1.64; 95% CI = 1.05-2.56; p = .03) than daughters of controls and 75% higher stress-responsive cortisol (ratio = 1.75; 95% CI = 1.04-2.94; p = .04) than daughters of preconception-only MDD mothers. HSD11B2 methylation moderated links between prenatal MDD and baseline cortisol (p = .02), with 1% methylation decreases associated with 9% increased baseline cortisol in infants of prenatal MDD mothers (ratio = 1.09; 95% CI = 1.01-1.16). SLC6A4 expression moderated links between prenatal MDD and cortisol response among boys alone (p = .007), with 10-fold increases in expression associated with threefold increases in stress-responsive cortisol (ratio = 2.87; 95% CI = 1.39-5.93) in sons of control mothers.

CONCLUSIONS

Results highlight specificity of associations between prenatal versus preconception MDD and cortisol regulation and the importance and complexity of placenta glucocorticoid and serotonergic pathways underlying the intergenerational transmission of risk from maternal adversity.

Maternal depression attenuates newborn vitamin D concentrations in winter-spring: a prospective population-based study

We aimed to investigate whether the newborns of mothers with maternal depression (MD) had lower vitamin D levels than newborns of non-MD (NMD) mothers and identify the potential mechanism underlying this association. Maternal depressive symptoms in late pregnancy and concentrations of cord blood 25 hydroxyvitamin D (25(OH)D) were measured in 1491 mother-infant pairs. Data on maternal sociodemographic characteristics, health status, lifestyle and birth outcomes were prospectively collected. For infants born in winter-spring, the infants of MD mothers had significantly reduced concentrations of 25(OH) D (adjusted β = −3.51 nmol/L; 95% CI: −6.19, −0.84; P = 0.010) and lower birth weight (3267 ± 470 g vs 3348 ± 598 g, F = 4.64, P = 0.031), compared with the infants of NMD mothers. A significant, inverse linear relationship was noted between maternal depression scores and the concentration of 25(OH)D for infants born in winter-spring (adjusted β = −0.158; 95% CI: −0.259, −0.057). The significant, inverse linear relationship between maternal depression scores and fetomaternal ratios of 25(OH) D was also observed among the infants born in winter-spring (adjusted β = −0.005; 95% CI: −0.008, −0.003). MD appears to significantly attenuate the vitamin D concentrations and birth weight of infants born in winter-spring. A decreased fetomaternal ratio of 25(OH)D might be involved in this biological pathway.

Does maternal mental well-being in pregnancy impact the early human epigenome?

There is considerable interest in the potential nongenetic transmission of a suite of mental health conditions across generations, with epigenetics emerging as a candidate mediator of such effects. This review summarizes findings from 22 studies measuring candidate gene DNA methylation and seven epigenome-wide association studies of offspring epigenetic profile in women with adverse mental wellbeing measures (stress, depression or anxiety) in pregnancy. Despite some compelling evidence to suggest an association, there is a lack of reproducible findings, potentially linked to a number of limitations to this research and the field more broadly. Large cohorts with well characterized exposures across pregnancy are now needed. There is exciting potential that epigenetics may help explain some of the link between maternal wellbeing and child health outcomes, thereby informing novel interventions, but future studies must address current limitations to advance translational knowledge in this area.

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.

Early origins of mental disorder - risk factors in the perinatal and infant period

BACKGROUND

There is increasing understanding of the significance of early neurodevelopment in establishing risk for the range of mental disorders. Models of the early aetiology of mental disorders are complex with a range of potential factors from genetic and epigenetic to environmental influencing neurological and psychological development. Whilst the mechanisms are not fully understood, this paper provides an overview of potential biological and neurobiological factors that might be involved.

METHOD

An aetiological model is presented and discussed. The discussion includes a range of risk factors for mental disorder. Maternal anxiety disorder is presented and reviewed as an example of the interaction of placental, epigenetic and early parenting factors elevating risk of poor neonatal outcome.

RESULTS

Available evidence points to the importance of in-utero influences as well as the role of early attachment and emotional care. Transgenerational mechanisms such as the impact of maternal mental disorder on foetal development are important models for examination of early risk. Maternal anxiety, as an example, is a significant risk factor for compromised mental health.

CONCLUSIONS

Development of models for understanding the early origins of mental disorder is an important step in elaborating risk reduction strategies. Comprehensive early identification of risk raises the possibility of preventive interventions.

Placental and fetal effects of antenatal exposure to antidepressants or untreated maternal depression

OBJECTIVE

To assess systematically the effects of antidepressants and untreated maternal depression on human placenta and the developing fetus.

METHODS

Pertinent medical literature information was identified using MEDLINE/PubMed, SCOPUS and EMBASE. Electronic searches, limited to human studies published in English, provided 21 studies reporting primary data on placental and fetal effects of antidepressant exposure or untreated gestational depression.

RESULTS

The impact of antidepressants and non-medicated maternal depression on placental functioning and fetal biochemical architecture seems to be demonstrated, although its clinical significance remains unclear. More robust data seem to indicate that exposure to either antidepressants or untreated maternal depression may induce epigenetic changes and interfere with the physiological fetal behavior. Two cases of iatrogenic fetal tachyarrhythmia have also been reported.

CONCLUSIONS

Future research should clarify the clinical relevance of the impact of antidepressant and untreated maternal depression exposure on placental functioning. Moreover, ultrasound studies investigating fetal responses to antidepressants or maternal depressive symptoms are mandatory. This assessment should be performed during the whole duration of gestational period, when different fetal behavioral patterns become progressively detectable. Analyses of biochemical and epigenetic modifications associated with maternal mood symptoms and antidepressant treatment should also be implemented.

Methylation of the Glucocorticoid Receptor (NR3C1) in Placenta Is Associated with Infant Cry Acoustics

Epigenetic mechanisms regulating expression of the glucocorticoid receptor gene (NR3C1) promoter may influence behavioral and biological aspects of stress response in human infants. Acoustic features of infant crying are an indicator of neurobehavioral and neurological status not yet investigated in relation to epigenetic mechanisms. We examined NR3C1 methylation in placental tissue from a series of 120 healthy newborn infants in relation to a detailed set of acoustic features extracted from newborn infant cries. We identified significant associations of NR3C1 methylation with energy variation in infants' cries as well as with the presence of very high fundamental frequency in cry utterances. The presence of high fundamental frequency in cry (above 1 kHz) has been linked to poor vocal tract control, poor regulation of stress response, and may be an indicator or poor neurobehavioral integrity. Thus, these results add to evidence linking epigenetic alteration of the NR3C1 gene in the placenta to neurodevelopmental features in infants.

Effects of Maternal Anxiety Disorders on Infant Self-Comforting Behaviors: The Role of Maternal Bonding, Infant Gender and Age

BACKGROUND/AIMS

We investigated the links between maternal bonding, maternal anxiety disorders, and infant self-comforting behaviors. Furthermore, we looked at the moderating roles of infant gender and age.

METHODS

Our sample (n = 69) comprised 28 mothers with an anxiety disorder (according to DSM-IV criteria) and 41 controls, each with their 2.5- to 8-month-old infant (41 females and 28 males). Infant behaviors were recorded during the Face-to-Face Still-Face paradigm. Maternal bonding was assessed by the Postpartum Bonding Questionnaire.

RESULTS

Conditional process analyses revealed that lower maternal bonding partially mediated between maternal anxiety disorders and increased self-comforting behaviors but only in older female infants (over 5.5 months of age). However, considering maternal anxiety disorders without the influence of bonding, older female infants (over 5.5 months of age) showed decreased rates of self-comforting behaviors, while younger male infants (under 3 months of age) showed increased rates in the case of maternal anxiety disorder.

CONCLUSIONS

The results suggest that older female infants (over 5.5 months of age) are more sensitive to lower maternal bonding in the context of maternal anxiety disorders. Furthermore, results suggest a different use of self-directed regulation strategies for male and female infants of mothers with anxiety disorders and low bonding, depending on infant age. The results are discussed in the light of gender-specific developmental trajectories.

The Placenta as a Mediator of Stress Effects on Neurodevelopmental Reprogramming

Adversity experienced during gestation is a predictor of lifetime neuropsychiatric disease susceptibility. Specifically, maternal stress during pregnancy predisposes offspring to sex-biased neurodevelopmental disorders, including schizophrenia, attention deficit/hyperactivity disorder, and autism spectrum disorders. Animal models have demonstrated disease-relevant endophenotypes in prenatally stressed offspring and have provided unique insight into potential programmatic mechanisms. The placenta has a critical role in the deleterious and sex-specific effects of maternal stress and other fetal exposures on the developing brain. Stress-induced perturbations of the maternal milieu are conveyed to the embryo via the placenta, the maternal-fetal intermediary responsible for maintaining intrauterine homeostasis. Disruption of vital placental functions can have a significant impact on fetal development, including the brain, outcomes that are largely sex-specific. Here we review the novel involvement of the placenta in the transmission of the maternal adverse environment and effects on the developing brain.

Maternal Prenatal Mental Health and Placental 11β-HSD2 Gene Expression: Initial Findings from the Mercy Pregnancy and Emotional Wellbeing Study

High intrauterine cortisol exposure can inhibit fetal growth and have programming effects for the child's subsequent stress reactivity. Placental 11beta-hydroxysteroid dehydrogenase (11β-HSD2) limits the amount of maternal cortisol transferred to the fetus. However, the relationship between maternal psychopathology and 11β-HSD2 remains poorly defined. This study examined the effect of maternal depressive disorder, antidepressant use and symptoms of depression and anxiety in pregnancy on placental 11β-HSD2 gene (HSD11B2) expression. Drawing on data from the Mercy Pregnancy and Emotional Wellbeing Study, placental HSD11B2 expression was compared among 33 pregnant women, who were selected based on membership of three groups; depressed (untreated), taking antidepressants and controls. Furthermore, associations between placental HSD11B2 and scores on the State-Trait Anxiety Inventory (STAI) and Edinburgh Postnatal Depression Scale (EPDS) during 12-18 and 28-34 weeks gestation were examined. Findings revealed negative correlations between HSD11B2 and both the EPDS and STAI (r = -0.11 to -0.28), with associations being particularly prominent during late gestation. Depressed and antidepressant exposed groups also displayed markedly lower placental HSD11B2 expression levels than controls. These findings suggest that maternal depression and anxiety may impact on fetal programming by down-regulating HSD11B2, and antidepressant treatment alone is unlikely to protect against this effect.

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.

Maternal depressive symptoms during pregnancy, placental expression of genes regulating glucocorticoid and serotonin function and infant regulatory behaviors

BACKGROUND

Glucocorticoids and serotonin may mediate the link between maternal environment, fetal brain development and 'programming' of offspring behaviors. The placenta regulates fetal exposure to maternal hormonal signals in animal studies, but few data address this in humans. We measured prospectively maternal depressive symptoms during pregnancy and mRNAs encoding key gene products determining glucocorticoid and serotonin function in term human placenta and explored associations with infant regulatory behaviors.

METHOD

Bi-weekly self-ratings of the Center for Epidemiologic Studies Depression Scale from 12th to 13th gestational week onwards and term placental mRNAs of 11beta-hydroxysteroid dehydrogenase type 2 (HSD2B11), type 1 (HSD1B11), glucocorticoid (NR3C1), mineralocorticoid receptors (NR3C2) and serotonin transporter (SLC6A4) were obtained from 54 healthy mothers aged 32.2 ± 5.3 years with singleton pregnancies and without pregnancy complications. Infant regulatory behaviors (crying, feeding, spitting, elimination, sleeping and predictability) were mother-rated at 15.6 ± 4.2 days.

RESULTS

Higher placental mRNA levels of HSD2B11 [0.41 standard deviation (s.d.) unit increase per s.d. unit increase; 95% confidence interval (CI) 0.13-0.69, p = 0.005], HSD1B11 (0.30, 0.03-0.57, p = 0.03), NR3C1 (0.44, 0.19-0.68, p = 0.001) and SLC6A4 (0.26, 0.00-0.53, p = 0.05) were associated with more regulatory behavioral challenges of the infant. Higher placental NR3C1 mRNA partly mediated the association between maternal depressive symptoms during pregnancy and infant regulatory behaviors (p < 0.05).

CONCLUSIONS

Higher placental expression of genes regulating feto-placental glucocorticoid and serotonin exposure is characteristic of infants with more regulatory behavioral challenges. Maternal depression acts, at least partly, via altering glucocorticoid action in the placenta to impact on offspring regulatory behaviors.

Maternal distress associates with placental genes regulating fetal glucocorticoid exposure and IGF2: Role of obesity and sex

Maternal emotional distress symptoms, including life satisfaction, anxiety and depressed mood, are worse in Severely Obese (SO) than lean pregnancy and may alter placental genes regulating fetal glucocorticoid exposure and placental growth. We hypothesised that the associations between increased maternal distress symptoms and changes in placental gene expression including IGF2 and genes regulating fetal glucocorticoid exposure are more pronounced in SO pregnancy. We also considered whether there were sex-specific effects. Placental mRNA levels of 11β-HSDs, NR3C1-α, NR3C2, ABC transporters, mTOR and the IGF2 family were measured in term placental samples from 43 lean (BMI≤25kg/m(2)) and 50 SO (BMI≥40kg/m(2)) women, in whom distress symptoms were prospectively evaluated during pregnancy. The mRNA levels of genes with a similar role in regulating fetal glucocorticoid exposure were strongly inter-correlated. Increased maternal distress symptoms associated with increased NR3C2 and IGF2 isoform 1(IGF2-1) in both lean and SO group (p≤0.05). Increased distress was associated with higher ABCB1 and ABCG2 mRNA levels in SO but lower ABCB1 and higher 11β-HSD1 mRNA levels in lean (p≤0.05) suggesting a protective adaptive response in SO placentas. Increased maternal distress associated with reduced mRNA levels of ABCB1, ABCG2, 11β-HSD2, NR3C1-α and IGF2-1 in placentas of female but not male offspring. The observed sex differences in placental responses suggest greater vulnerability of female fetuses to maternal distress with potentially greater fetal glucocorticoid exposure and excess IGF2. Further studies are needed to replicate these findings and to test whether this translates to potentially greater negative outcomes of maternal distress in female offspring in early childhood.

Maternal depressive symptoms throughout pregnancy are associated with increased placental glucocorticoid sensitivity

BACKGROUND

Maternal prenatal depression predicts post-partum depression and increases risk of prematurity and low birth weight. These effects may be mediated by altered placental function. We hypothesized that placental function would be influenced by the gestational week of experiencing depressive symptoms and aimed to examine associations between maternal depressive symptoms during pregnancy and placental expression of genes involved in glucocorticoid and serotonin transfer between mother and fetus.

METHOD

We studied women participating in a prospective pregnancy cohort: the Prediction and Prevention of Preeclampsia (PREDO) Study, Helsinki, Finland. Maternal depressive symptoms were assessed at 2-week intervals throughout pregnancy in 56 healthy women with singleton, term pregnancies. Messenger ribonucleic acid (mRNA) levels of glucocorticoid (GR) and mineralocorticoid (MR) receptors and serotonin transporter (SLC6A4), 11β-hydroxysteroid dehydrogenase type 1 (HSD1) and 2 (HSD2) were quantified in placental biopsies.

RESULTS

In adjusted analyses women who reported higher depressive symptoms across the whole pregnancy had higher mRNA levels of GR [effect size 0.31 s.d. units, 95% confidence interval (CI) 0.01-0.60, p = 0.042] and MR (effect size 0.34 s.d. units, 95% CI 0.01-0.68, p = 0.047). These effects were significant for symptoms experienced in the third trimester of pregnancy for GR; findings for MR were also significant for symptoms experienced in the second trimester. GR and MR mRNA levels increased linearly by having the trimester-specific depressive symptoms scores 0, 1 or 2-3 times above the clinical cut-off for depression (p = 0.003, p = 0.049, respectively, and p = 0.004, p = 0.15 in adjusted analyses).

CONCLUSIONS

Our findings offer potential gestational-age-specific mechanisms linking maternal depressive symptoms during pregnancy via placental biology. Future studies will test whether these also link with adverse offspring outcomes.