Affective changes during the postpartum period: Influences of genetic and experiential factors

Joint effects of traffic-related air pollution and hypertensive disorders of pregnancy on maternal postpartum depressive and anxiety symptoms

BACKGROUND

Ambient air pollution has been linked to postpartum depression. However, few studies have investigated the effects of traffic-related NOx on postpartum depression and whether any pregnancy-related factors might increase susceptibility.

OBJECTIVES

To evaluate the association between traffic-related NOx and postpartum depressive and anxiety symptoms, and effect modification by pregnancy-related hypertension.

METHODS

This study included 453 predominantly low-income Hispanic/Latina women in the MADRES cohort. Daily traffic-related NOx concentrations by road class were estimated using the California LINE-source dispersion model (CALINE4) at participants' residential locations and averaged across pregnancy. Postpartum depressive and anxiety symptoms were evaluated by a validated questionnaire (Postpartum Distress Measure, PDM) at 1, 3, 6 and 12 months postpartum. Multivariate linear regressions were performed to estimate the associations at each timepoint. Interaction terms were added to the linear models to assess effect modification by hypertensive disorders of pregnancy (HDPs). Repeated measurement analyses were conducted by using mixed effect models.

RESULTS

We found prenatal traffic-related NOx was associated with increased PDM scores. Specifically, mothers exposed to an IQR (0.22 ppb) increase in NOx from major roads had 3.78% (95% CI: 0.53-7.14%) and 5.27% (95% CI: 0.33-10.45%) significantly higher 3-month and 12-month PDM scores, respectively. Similarly, in repeated measurement analyses, higher NOx from major roads was associated with 3.06% (95% CI: 0.43-5.76%) significantly higher PDM scores across the first year postpartum. Effect modification by HDPs was observed: higher freeway/highway and total NOx among mothers with HDPs were associated with significantly higher PDM scores at 12 months postpartum compared to those without HDPs.

IMPACT

This study shows that prenatal traffic-related air pollution was associated with postpartum depressive and anxiety symptoms. The study also found novel evidence of greater susceptibility among women with HDPs, which advances the understanding of the relationships between air pollution, maternal cardiometabolic health during pregnancy and postpartum mental health. Our study has potential implications for clinical intervention to mitigate the effects of traffic-related pollution on postpartum mental health disorders. The findings can also offer valuable insights into urban planning strategies concerning the implementation of emission control measures and the creation of green spaces.

Risk Factors for Postpartum Depression Based on Genetic and Epigenetic Interactions

Postpartum depression (PPD) is a serious mood disorder that tends to occur after the delivery, which may bring lifelong consequences to women and their families in terms of family relationships, social relationships, and mental health. Currently, various risk factors including environmental factors and genetic factors that may induce postpartum depression have been extensively studied. In this review, we suggest that postpartum women's susceptibility to postpartum depression may be the result of the interaction between the genes associated with postpartum depression as well as the interaction between genetic and environmental factors. We reviewed the genes that have been studied in postpartum depression, including genes related to the synthesis, metabolism, and transport of monoamine neurotransmitters, key molecules of the HPA axis, and the kynurenine pathway. These studies have found more or less gene-gene and gene-environment interactions, so we will discuss these issues in more detail. However, so far, the conclusions of these risk factors, especially genetic factors, are not completely consistent in the occurrence and exacerbation of symptoms in postpartum depression, and it is not clear how these risk factors specifically participate in the pathological mechanism of the disease and play a role. We conclude that the role of genetic polymorphisms, including genetic and epigenetic processes, in the occurrence and development of postpartum depression, is complex and ambiguous. We also note that interactions between multiple candidate genes and the environment have been suggested as causes of depression, suggesting that more definitive research is needed to understand the heritability and susceptibility of PPD. Overall, our work supports the hypothesis that postpartum depression is more likely to be caused by a combination of multiple genetic and environmental factors than by a single genetic or environmental influence.

Food security and diet quality in a racially diverse cohort of postpartum women in the USA

Food insecurity has been associated with poor diet, but few studies focused on the postpartum period - an important time for women's health. We examined associations between food security and diet quality in postpartum women and assessed whether participation in federal food assistance programmes modified this potential relation. Using longitudinal data, we analysed the association between food security at 3 months postpartum and a modified Alternate Healthy Eating Index-2010 (AHEI) at 6 months postpartum (excluding alcohol). We conducted multivariable linear regressions examining associations between food security and AHEI. We assessed two food assistance programmes as potential effect modifiers. The sample included 363 postpartum women from the Nurture study, located in the Southeastern USA (2013-2017). Among women, 64·4 % were Black and 45·7 % had a high school diploma or less. We found no evidence of an interaction between food security and two federal food assistance programmes. In adjusted models, marginal, low and very low food security were not associated with AHEI. However, low (β: -0·64; 95 % CI -1·15, -0·13; P = 0·01) and very low (β: -0·57; 95 % CI -1·02, -0·13; P = 0·01) food security were associated with greater trans fat intake. Food security status was not associated with overall diet quality but was associated with higher trans fat (low and very low) and more moderate alcohol (marginal) intake. Future studies should assess the consistency and generalisability of these findings.

The Maternal Disintegrative Responses Scale (MDRS): Development and initial validation

OBJECTIVE

This study aimed to design and examine the validity of the Maternal Disintegrative Responses Scale (MDRS) to assess intrusive thoughts and dissociative experiences in the postpartum period.

METHOD

A convenience sample of 455 mothers whose babies were up to 12 months old completed the MDRS and a series of questionnaires assessing postnatal depression (Edinburgh Postnatal Depression Scale [EPDS]), childbirth-related post-traumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), and general symptoms of dissociation.

RESULTS

The final scale consists of eight items tapping two dimensions, intrusive thoughts and dissociative experiences, and displays good psychometric properties. Both factors were found to be related to EPDS, PTSD OCD, and general symptoms of dissociation. Primiparous women scored higher than multiparous women on both dimensions, and mothers of infants up to 3 months old scored higher on dissociative experiences than those whose infants were aged 4-12 months.

CONCLUSIONS

The MDRS can contribute to the theoretical and practical conceptualization and assessment of these phenomena.

Fleur G, Mukona L, Hernandez E, Lamberty N. Peripartum Complications as Risk Factors for Postpartum Psychosis: A Systemic Review

The aim of this research paper is to conduct a systematic review of periparturient complications as risk factors of postpartum psychosis. The investigation of risk factors for maternal psychosis following childbirth is complicated by the risk of confounding by a previous psychiatric history; therefore, this systematic review focuses on labor complications as risk factors among women without any previous psychiatric hospitalizations or diagnoses.

Articles were collected and analyzed from the PubMed, MEDLINE, and Cochrane Review Library databases, as well as Clinicaltrials.gov, in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Article abstracts and article titles of the identified publications were screened independently by all seven authors, and studies were selected if they met the following inclusion criteria: patients were diagnosed with postpartum psychosis per the guidelines in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-V), DSM-IV or World Health Organization’s ICD-10 Classification of Mental and Behavioral Disorders; patients presented with no prior psychiatric diagnoses, hospitalizations or history; and the study evaluated the association of periparturient complications to first-onset postpartum psychosis, excluding narrative reviews, systematic reviews, or meta-analyses.

Fifteen case-control, cohort, and case report studies, with thousands of patients, were selected to investigate the correlation between perinatal complications and first-onset post-partum psychosis. Obstetric complications during childbirth significantly predisposed for postpartum psychosis in certain individual studies but did not reveal an association in others.

More studies must be implemented to elaborate on this limited scope.

GABA in the medial prefrontal cortex regulates anxiety-like behavior during the postpartum period

The postpartum period is commonly accompanied by emotional changes, which for many new mothers includes a reduction in anxiety. Previous research in rodents has shown that the postpartum attenuation in anxiety is dependent on offspring contact and has further implicated enhanced GABAergic neurotransmission as an underlying mechanism. However, the specific brain regions where GABA acts to regulate the offspring-induced reduction in postpartum anxiety requires further investigation. Here, we test the hypothesis that offspring interactions suppress anxiety-like behavior in postpartum female rats via GABA signaling in the medial prefrontal cortex (mPFC). Our results show a postpartum reduction in anxiety-like behavior, an effect which was abolished by localized infusion of the GABAA receptor antagonist bicuculline in the mPFC. We also show that activation of GABAA receptors in the mPFC by the agonist muscimol was effective in restoring anxiolyisis in mothers separated from their pups. Lastly, we show that heightened anxiety-like behavior in pup-separated mothers was accompanied by a lower number and percentage of activated GABAergic neurons within the mPFC. Together, these results suggest that mother-offspring interactions reduce anxiety-like behavior in postpartum females via GABAA neurotransmission in the mPFC and in doing so provide insight into mechanisms that may become dysfunctional in mothers who experience high postpartum anxiety.

A Study on Postpartum Depression and its Association with Infant Feeding Practices and Infant Nutritional Status among Mothers Attending the Anganwadi Centers of Valsad District, Gujarat, India

Background:

Systematic reviews on postpartum depression (PPD) suggest that PPD mothers are more likely to interrupt exclusive breastfeeding with inappropriate feeding practices resulting malnutrition in child. A community-based study was planned with the objective to find the risk factors associated with PPD and its possible association on infant feeding practices and infant nutritional status.

Materials and Methods:

This was a cross-sectional study conducted among 116 postpartum mothers attending Anganwadi centers under the Urban Health Training Centre and Rural Health Training Centre of Medical College. A purposive sampling technique was applied. Informed and written consent in local language was taken. Data were collected in predesigned, pretested, and semi-structured pro forma. The mothers were screened for possible PPD using the 10-item well-validated Edinburgh PPD Scale in Gujarati language. The cutoff point is score more than 10.5 based on previous studies. Infant's nutritional status and breastfeeding practices were assessed according to the WHO Growth Chart and Infant and Young Child Feeding guidelines.

Results:

(1) 6.8% of the prevalence of PPD was reported in the study; (2) sociodemographic factors such as relationship of mothers with in-laws/husbands, help at home in childcare, literacy status, age at marriage and first child, and own desired/in-laws of sex of child are found to be significantly associated with PPD. (3) The Association of PPD and poor nutritional status of child was statistically significant.

Conclusions:

The study highlights the need of screening for PPD in the community. The potential risk factors for PPD can be taken into consideration during routine antenatal/postnatal care and for planning of preventive strategies.

Sex-biased impact of endocrine disrupting chemicals on behavioral development and vulnerability to disease: Of mice and children

Sex is a fundamental biological characteristic that influences many aspects of an organism's phenotype, including neurobiological functions and behavior as a result of species-specific evolutionary pressures. Sex differences have strong implications for vulnerability to disease and susceptibility to environmental perturbations. Endocrine disrupting chemicals (EDCs) have the potential to interfere with sex hormones functioning and influence development in a sex specific manner. Here we present an updated descriptive review of findings from animal models and human studies regarding the current evidence for altered sex-differences in behavioral development in response to early exposure to EDCs, with a focus on bisphenol A and phthalates. Overall, we show that animal and human studies have a good degree of consistency and that there is strong evidence demonstrating that EDCs exposure during critical periods of development affect sex differences in emotional and cognitive behaviors. Results are more heterogeneous when social, sexual and parental behaviors are considered. In order to pinpoint sex differences in environmentally-driven disease vulnerabilities, researchers need to consider sex-biased developmental effects of EDCs.

Gender discrimination and women's HPA activation to psychosocial stress during the postnatal period

Stress due to discrimination may contribute to physiological dysregulation and health risk during the postnatal period. This study examined longitudinal associations between gender discrimination and women's cortisol responses to subsequent stress. Mothers (N = 79) reported gender discrimination and completed mother-infant stress tasks with saliva sampling for cortisol at 6, 12, and 18 months postnatal. Multilevel modeling results indicated more overall gender discrimination was associated with higher cortisol. Changes in gender discrimination were not associated with cortisol over time. Gender discrimination may be a factor in women's postnatal stress and associated health risk via the sensitization of physiological stress responses.

Influencing factors and correlation of anxiety, psychological stress sources, and psychological capital among women pregnant with a second child in Guangdong and Shandong Province

BACKGROUND

After the one-child policy has been effective for over 30 years, China implemented the universal two-child policy in 2015. The number of high-risk pregnant women had increased dramatically ever since, increasing negative health outcomes for both mothers and children. Our study aims to investigate the status of anxiety, psychological stress sources, and psychological capital among women pregnant with a second child, and to assess influencing factors and correlations, providing scientific basis for promoting women's health during pregnancy.

METHODS

We recruited 513 participants from maternity hospitals in Guangdong and Shandong Province. All participants completed the Zung Self-Rating Anxiety Scale (SAS), Pregnant women psychological stress sources questionnaire and the psychological capital questionnaire (PCQ-24).

RESULTS

The prevalence of anxiety of women pregnant with a second child was 27.5%. The score of psychological stress sources was 74.93 ± 16.07. The risk factors for the anxiety of the women pregnant with a second child included low education level of the husband, gender expectation and the sources of psychological stress of the pregnant woman. The risk factors for psychological stress were dissatisfaction of residence and unplanned pregnancy. The main factors influencing psychological capital were the participants' education level, whether they have learned antenatal care knowledge and satisfaction with the residence.

LIMITATIONS

All participants were recruited only from tertiary hospitals in Guangdong and Shandong province.

CONCLUSIONS

Anxiety and psychological stress is prevalent during pregnancy among women pregnant with a second child in Guangdong and Shandong. Psychological capital was a protective factor for anxiety.

Mothers, Fathers, and Others: Neural Substrates of Parental Care

Parental care is essential for the survival of offspring in altricial mammalian species. However, in most mammals, virgin females tend to avoid or attack infants. Moreover, most males demonstrate avoidance and aggression toward infants, and have little to no involvement in parental care. What mechanisms suppress avoidance, and support approach towards pups, to promote maternal care? In biparental and cooperatively breeding species, what mechanisms allow nonmothers (i.e., fathers and alloparents) to demonstrate parental care? In this review we consider the mechanisms that subserve parental care in mothers, fathers, and others (i.e., alloparents). We emphasize recent discoveries and research trends with particular emphasis on neuroendocrinology, neuroplasticity, transcriptomics, and epigenetics. Finally, we consider outstanding questions and outline opportunities for future research.

The long and short term effects of motherhood on the brain

Becoming a mother is associated with dramatic changes in physiology, endocrinology, immune function, and behaviour that begins during pregnancy and persists into the postpartum. Evidence also suggests that motherhood is accompanied by long-term changes in brain function. In this review, we summarize the short (pregnancy and postpartum) and long-term (beyond the postpartum and into middle age) effects of pregnancy and motherhood on cognition, neuroplasticity, and neuroimmune signalling. We also discuss the effects of previous history of pregnancy and motherhood (parity) on brain health and disease (neurodegenerative diseases and stroke outcomes) and on efficacy of hormone and antidepressant treatments. Finally, we argue that pregnancy and motherhood are unique female experiences that need to be taken into account to better understand female brain function and aging.

Serotonin and motherhood: From molecules to mood

Emerging research points to a valuable role of the monoamine neurotransmitter, serotonin, in the display of maternal behaviors and reproduction-associated plasticity in the maternal brain. Serotonin is also implicated in the pathophysiology of numerous affective disorders and likely plays an important role in the pathophysiology of maternal mental illness. Therefore, the main goals of this review are to detail: (1) how the serotonin system of the female brain changes across pregnancy and postpartum; (2) the role of the central serotonergic system in maternal caregiving and maternal aggression; and (3) how the serotonin system and selective serotonin reuptake inhibitor medications (SSRIs) are involved in the treatment of maternal mental illness. Although there is much work to be done, studying the central serotonin system's multifaceted role in the maternal brain is vital to our understanding of the processes governing matrescence and the maintenance of motherhood.

Brain plasticity in pregnancy and the postpartum period: links to maternal caregiving and mental health

Pregnancy and the postpartum period involve numerous physiological adaptations that enable the development and survival of the offspring. A distinct neural plasticity characterizes the female brain during this period, and dynamic structural and functional changes take place that accompany fundamental behavioral adaptations, stimulating the female to progress from an individual with self-directed needs to being responsible for the care of another life. While many animal studies detail these modifications, an emerging body of research reveals the existence of reproduction-related brain plasticity in human mothers too. Additionally, associations with aspects of maternal caregiving point to adaptive changes that benefit a woman's transition to motherhood. However, the dynamic changes that affect a woman's brain are not merely adaptive, and they likely confer a vulnerability for the development of mental disorders. Here, we review the changes in brain structure and function that a woman undergoes during the peripartum period, outlining associations between these neural alterations and different aspects of maternal care. We additionally discuss peripartum mood disorders and postpartum psychosis, and review the neuroimaging studies that investigate the neural bases of these conditions.

Impact of Pregnancy and Lactation on the Long-Term Regulation of Energy Balance in Female Mice

During pregnancy and lactation, the maternal body undergoes many changes in the regulation of appetite, body weight, and glucose homeostasis to deal with the metabolic demands of the growing fetus and subsequent demands of providing milk for offspring. The aim of the current study was to investigate the consequences of one reproductive cycle of pregnancy and lactation on the long-term regulation of energy homeostasis. After weaning of pups, reproductively experienced (RE) mice maintained a higher body weight compared with age-matched control mice. Although there was no difference in daily food intake or the feeding response to exogenous leptin administration, RE mice were less active than age-matched control mice as measured by average daily x + y beam breaks or average daily ambulatory distance. RE and age-matched controls were also subjected to either a high-fat diet or control diet for 6 weeks to determine if experiencing a major challenge to energy homeostasis such as pregnancy and lactation leads to increased susceptibility to a second challenge to this system. Although both RE and control mice gained a similar amount of body weight on the high-fat diet, only the RE mice had impaired glucose tolerance when consuming the high-fat diet, thus demonstrating an increased susceptibility to the negative consequences of a high-fat diet after pregnancy and lactation. Overall, these data indicate that pregnancy and lactation have long-term consequences on energy homeostasis in mothers.

Disrupted Spontaneous Neural Activity Related to Cognitive Impairment in Postpartum Women

Purpose: Prior research has demonstrated that the postpartum period is associated with an increased risk of cognitive impairment. This study aims to investigate whether disrupted spontaneous neural activity exists in postpartum women without depression using resting-state functional magnetic resonance imaging (rs-fMRI) and to detect the relationship between these abnormalities and cognitive impairment.

Materials and Methods: Postpartum women (n = 22) were compared with age- and education-matched nulliparous women (n = 23) using rs-fMRI. We calculated the amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values to evaluate spontaneous neural activity and detect the relationship between rs-fMRI data and cognitive performance.

Results: Relative to nulliparous women, postpartum women had significantly decreased ALFF and ReHo values primarily in the left posterior cingulate cortex (PCC) and prefrontal cortex and increased ALFF values in left cerebellar posterior lobe. We found a positive correlation between the ALFF and ReHo values in the PCC and the complex figure test (CFT)-delayed scores in postpartum women (r = 0.693, p = 0.001; r = 0.569, p = 0.011, respectively). Moreover, the clock-drawing test (CDT) scores showed positive correlations with the ALFF and ReHo values in the right superior frontal gyrus (SFG; r = 0.492, p = 0.033; r = 0.517, p = 0.023, respectively).

Conclusion: Our combined ALFF and ReHo analyses revealed decreased spontaneous neural activity, mainly in the PCC and prefrontal cortex, which was correlated with specific impaired cognitive functioning in postpartum women. This study may elucidate the neurophysiological mechanisms underlying postpartum cognitive impairment and enhance our understanding of the neurobiological aspects of the postpartum period.

Sociodemographic, obstetric characteristics, antenatal morbidities, and perinatal depressive symptoms: A three-wave prospective study

Objectives

This study aimed (1) to investigate the pattern of perinatal depressive symptoms, and (2) to determine the relationships between sociodemographic characteristics, obstetric factors, antenatal morbidities, postnatal conditions, and perinatal depressive symptoms using a structural equation model (SEM).

Method

A three-wave prospective longitudinal design was used for 361 women in their second trimester, third trimester, and at six weeks postpartum. The Edinburgh Postnatal Depression Scale (EPDS) was used to assess the depressive symptoms.

Results

The intensity of depressive symptoms was the highest in the second trimester among the three waves. The SEM showed that unmarried status, unplanned pregnancy, gestational diabetes, and headache were significantly associated with EPDS in the first and second waves. The EPDS in the first wave was able to predict the EPDS in the second and third waves. The SEM has satisfactorily fit with the data (chi-square/degree of freedom = 1.42, incremental fit index = 0.91, Tucker-Lewis index = 0.90, comparative fit index = 0.91, and root mean square error of approximation = 0.03).

Conclusion

The findings highlight the significance of monitoring depressive symptoms in the second trimester. Findings from this study could be useful in the design of effective intervention among women with unmarried status, unplanned pregnancy, gestational diabetes, and headache in order to reduce risk of perinatal depressive symptoms.

Increased systemic microbial translocation is associated with depression during early pregnancy

Plasma level of microbial translocation is a marker of mucosal permeability. Increased mucosal permeability ignites elevated microbial translocation and as a consequence of systemic inflammation. Pregnant women with depression have higher levels of inflammatory markers relative to pregnant women without depression, however, no studies have reported whether systemic microbial translocation will change in depressed women during pregnancy. In this study, we examined the plasma LPS level of depressed women during pregnancy. The results showed that the plasma LPS level was significantly increased in depressed mothers during their 8-12 weeks gestation compared to healthy controls. Compared to 8-12 weeks gestation, the plasma LPS levels were significantly decreased at 24-28 weeks gestation and 6-8 weeks postpartum in both depressed subjects and healthy controls. Furthermore, the plasma levels of pro-inflammatory cytokines (TNF-α and MCP/CCL2) associated with microbial translocation were significantly increased in depressed subjects during 8-12 weeks gestation compared to healthy controls. These results indicate that the level of microbial translocation is increased in depressed women during early pregnancy.

Postpartum Lactation-Mediated Behavioral Outcomes and Drug Responses in a Spontaneous Mouse Model of Obsessive-Compulsive Disorder

Using a spontaneous mouse model of obsessive-compulsive disorder (OCD), the current study evaluated the influence of postpartum lactation on the expression of compulsive-like behaviors, SSRI effectiveness, and the putative role of oxytocin and dopamine in mediating these lactation specific behavioral outcomes. Compulsive-like lactating mice were less compulsive-like in nest building and marble burying and showed enhanced responsiveness to fluoxetine (50 mg/kg) in comparison to compulsive-like nonlactating and nulliparous females. Lactating mice exhibited more anxiety-like behavior in the open field test compared to the nulliparous females, while chronic fluoxetine reduced anxiety-like behaviors. Blocking the oxytocin receptor with L368-899 (5 mg/kg) in the lactating mice exacerbated the compulsive-like and depression-like behaviors. The dopamine D2 receptor (D2R) agonist bromocriptine (10 mg/kg) suppressed marble burying, nest building, and central entries in the open field, but because it also suppressed overall locomotion in the open field, activation of the D2R receptor may have inhibited overall activity nonspecifically. Lactation- and fluoxetine-mediated behavioral outcomes in compulsive-like mice, therefore, appear to be partly regulated by oxytocinergic mechanisms. Serotonin immunoreactivity and serum levels were higher in lactating compulsive-like mice compared to nonlactating and nulliparous compulsive-like females. Together, these results suggest behavioral modulation, serotonergic alterations, and changes in SSRI effectiveness during lactation in compulsive-like mice. This warrants further investigation of postpartum events in OCD patients.

Pregnancy-related anxiety and depressive symptoms are associated with visuospatial working memory errors during pregnancy

BACKGROUND

Cognitive deficits, especially in memory and concentration, are often reported during pregnancy. Similar cognitive dysfunctions can also occur in depression and anxiety. To date, few studies have investigated the associations between cognitive deficits and psychiatric symptoms during pregnancy. This field is of interest because maternal cognitive functioning, and particularly its higher-order aspects are related to maternal well-being and caregiving behavior, as well as later child development.

METHODS

Pregnant women (N =230), reporting low (n =87), moderate (n =97), or high (n =46) levels of depressive, general anxiety and/or pregnancy-related anxiety symptoms (assessed repeatedly with EPDS, SCL-90/anxiety subscale, PRAQ-R2, respectively) were tested in mid-pregnancy for their cognitive functions. A computerized neuropsychological test battery was used.

RESULTS

Pregnant women with high or moderate level of psychiatric symptoms had significantly more errors in visuospatial working memory/executive functioning task than mothers with low symptom level. Depressive symptoms throughout pregnancy and concurrent pregnancy-related anxiety symptoms were significant predictors of the performance in the task. General anxiety symptoms were not related to visuospatial working memory.

LIMITATIONS

Cognitive functions were evaluated only at one time-point during pregnancy precluding causal conclusions.

CONCLUSIONS

Maternal depressive symptoms and pregnancy-related anxiety symptoms were both associated with decrements in visuospatial working memory/executive functioning. Depressive symptoms seem to present more stable relationship with cognitive deficits, while pregnancy-related anxiety was associated only concurrently. Future studies could investigate, how stable these cognitive differences are, and whether they affect maternal ability to deal with demands of pregnancy and later parenting.

Parenting in Animals

The study of parenting in animals has allowed us to come to a better understanding of the neural and physiological mechanisms that underlie mammalian parental behavior. The long-term effects of parenting (and parental abuse or neglect) on offspring, and the neurobiological changes that underlie those changes, have also been best studied in animal models. Our greater experimental control and ability to directly manipulate neural and hormonal systems, as well as the environment of the subjects, will ensure that animal models remain important in the study of parenting; while in the future, the great variety of parental caregiving systems displayed by animals should be more thoroughly explored. Most importantly, cross-talk between animal and human subjects research should be promoted.

Preadolescent Adversity Programs a Disrupted Maternal Stress Reactivity in Humans and Mice

BACKGROUND

Adverse childhood experiences (ACEs) are one of the greatest predictors of affective disorders for women. Periods of dynamic hormonal flux, including pregnancy, exacerbate the risk for affective disturbance and promote hypothalamic-pituitary-adrenal (HPA) axis dysregulation, a key feature of affective disorders. Little is understood as to how stress experienced in late childhood, defined as preadolescence, alters the programming unique to this period of brain maturation and its interaction with the hormonal changes of pregnancy and postpartum.

METHODS

Preadolescent female mice were exposed to chronic stress and examined for changes in their HPA axis during pregnancy and postpartum, including assessment of maternal-specific stress responsiveness and transcriptomics of the paraventricular nucleus of the hypothalamus. Translationally, pregnant women with low or high ACEs were examined for their maternal stress responsiveness.

RESULTS

As predicted, preadolescent stress in mice resulted in a significant blunting of the corticosterone response during pregnancy. Transcriptomic analysis of the paraventricular nucleus revealed widespread changes in expression of immediate early genes and their targets, supporting the likely involvement of an upstream epigenetic mechanism. Critically, in our human studies, the high ACE women showed a significant blunting of the HPA response.

CONCLUSIONS

This unique mouse model recapitulates a clinical outcome of a hyporesponsive HPA stress axis, an important feature of affective disorders, during a dynamic hormonal period, and suggests involvement of transcriptional regulation in the hypothalamus. These studies identify a novel mouse model of female ACEs that can be used to examine how additional life adversity may provoke disease risk or resilience.

The Neurobiology of Postpartum Anxiety and Depression

Ten to twenty percent of postpartum women experience anxiety or depressive disorders, which can have detrimental effects on the mother, child, and family. Little is known about the neural correlates of these affective disorders when they occur in mothers, but they do have unique neural profiles during the postpartum period compared with when they occur at other times in a woman's life. Given that the neural systems affected by postpartum anxiety and depression overlap and interact with the systems involved in maternal caregiving behaviors, mother-infant interactions are highly susceptible to disruption. Thus, there is an intricate interplay among maternal mental health, the mother-infant relationship, and the neurobiological mechanisms mediating them that needs to be the focus of future study.

A survey of neuroimmune changes in pregnant and postpartum female rats

During pregnancy and the postpartum period, the adult female brain is remarkably plastic exhibiting modifications of neurons, astrocytes and oligodendrocytes. However, little is known about how microglia, the brain's innate immune cells, are altered during this time. In the current studies, microglial density, number and morphological phenotype were analyzed within multiple regions of the maternal brain that are known to show neural plasticity during the peripartum period and/or regulate peripartum behavioral changes. Our results show a significant reduction in microglial density during late pregnancy and the early-mid postpartum period in the basolateral amygdala, medial prefrontal cortex, nucleus accumbens shell and dorsal hippocampus. In addition, microglia numbers were reduced postpartum in all four brain regions, and these reductions occurred primarily in microglia with a thin, ramified morphology. Across the various measures, microglia in the motor cortex were unaffected by reproductive status. The peripartum decrease in microglia may be a consequence of reduced proliferation as there were fewer numbers of proliferating microglia, and no changes in apoptotic microglia, in the postpartum hippocampus. Finally, hippocampal concentrations of the cytokines interleukin (IL)-6 and IL-10 were increased postpartum. Together, these data point to a shift in the maternal neuroimmune environment during the peripartum period that could contribute to neural and behavioral plasticity occurring during the transition to motherhood.

The birth of new neurons in the maternal brain: Hormonal regulation and functional implications

The maternal brain is remarkably plastic and exhibits multifaceted neural modifications. Neurogenesis has emerged as one of the mechanisms by which the maternal brain exhibits plasticity. This review highlights what is currently known about peripartum-associated changes in adult neurogenesis and the underlying hormonal mechanisms. We also consider the functional consequences of neurogenesis in the peripartum brain and extent to which this process may play a role in maternal care, cognitive function and postpartum mood. Finally, while most work investigating the effects of parenting on adult neurogenesis has focused on mothers, a few studies have examined fathers and these results are also discussed.

Neurogenesis and anxiety-like behavior in male California mice during the mate's postpartum period

Our understanding of postpartum anxiety (PPA) in fathers is limited, despite the negative consequences of anxiety on the father and child. Offspring contact reduces PPA in mothers; however, parallel investigations in fathers has gone unaddressed. Adult neurogenesis in the dentate gyrus (DG) contributes to anxiety regulation and is altered during the postpartum period, yet the effects of fatherhood on the production, or survival, of newborn cells in the DG, and the role of adult neurogenesis in PPA regulation, have not been examined. Using the biparental California mouse (Peromyscus californicus), we examined the relationships among postnatal day, anxiety-like behavior and adult neurogenesis in fathers. We hypothesized that attenuated anxiety-like behavior and enhanced adult neurogenesis would be observed when father-offspring contact was increased. We observed a reduction in anxiety-like behavior on the elevated plus-maze, but only at PND 16, a time of peak pup retrieval. Fatherhood reduced 1-week survival of newborn cells; however, surviving cells were maintained until 2 weeks postpartum. In contrast, non-fathers experienced a significant reduction in the survival of newborn cells between 1 and 2 weeks postpartum. Fatherhood also increased the numbers of newborn cells that expressed a neuronal phenotype. Collectively, these findings suggest that offspring interaction contributes to reductions in anxiety-like behavior and the maintenance of newborn neurons in the DG of fathers. These data contribute to our knowledge of the postpartum affective state in fathers, findings that may contribute to improved health of both the father and offspring.

Variable postpartum responsiveness among humans and other primates with "cooperative breeding": A comparative and evolutionary perspective

This article is part of a Special Issue "Parental Care".Until recently, evolutionists reconstructing mother-infant bonding among human ancestors relied on nonhuman primate models characterized by exclusively maternal care, overlooking the highly variable responsiveness exhibited by mothers in species with obligate reliance on allomaternal care and provisioning. It is now increasingly recognized that apes as large-brained, slow maturing, and nutritionally dependent for so long as early humans were, could not have evolved unless "alloparents" (group members other than genetic parents), in addition to parents, had helped mothers to care for and provision offspring, a rearing system known as "cooperative breeding." Here I review situation-dependent maternal responses ranging from highly possessive to permissive, temporarily distancing, rejecting, or infanticidal, documented for a small subset of cooperatively breeding primates. As in many mammals, primate maternal responsiveness is influenced by physical condition, endocrinological priming, prior experience and local environments (especially related to security). But mothers among primates who evolved as cooperative breeders also appear unusually sensitive to cues of social support. In addition to more "sapient" or rational decision-making, humankind's deep history of cooperative breeding must be considered when trying to understand the extremely variable responsiveness of human mothers.

Common and divergent psychobiological mechanisms underlying maternal behaviors in non-human and human mammals

Maternal interactions with young occupy most of the reproductive period for female mammals and are absolutely essential for offspring survival and development. The hormonal, sensory, reward-related, emotional, cognitive and neurobiological regulators of maternal caregiving behaviors have been well studied in numerous subprimate mammalian species, and some of the importance of this body of work is thought to be its relevance for understanding similar controls in humans. We here review many of the important biopsychological influences on maternal behaviors in the two best studied non-human animals, laboratory rats and sheep, and directly examine how the conceptual framework established by some of the major discoveries in these animal "models" do or do not hold for our understanding of human mothering. We also explore some of the limits for extrapolating from non-human animals to humans. We conclude that there are many similarities between non-human and human mothers in the biological and psychological factors influencing their early maternal behavior and that many of the differences are due to species-characteristic features related to the role of hormones, the relative importance of each sensory system, flexibility in what behaviors are exhibited, the presence or absence of language, and the complexity of cortical function influencing caregiving behaviors.