Pregnancy leads to long-lasting changes in human brain structure

Cortisol and testosterone concentrations during the prenatal and postpartum period forecast later caregiving quality in mothers and fathers

Given that parental caregiving quality affects child development from birth onwards, it is important to detect parents who are at risk for low-quality caregiving as early as possible, preferably before or soon after birth. This study investigated whether cortisol (CORT) and testosterone (T) measured during the last trimester of pregnancy and six weeks postpartum were associated with observed caregiving quality at child age 3 in mothers (N = 63) and fathers (N = 45). CORT and T were measured during an interaction with a simulator infant (pregnancy) and their own infant (postpartum). In mothers, no associations were found with CORT and T during pregnancy, but higher postpartum CORT during a mother-infant interaction was related to higher caregiving quality during toddlerhood. In fathers, the association between T during pregnancy and caregiving quality in toddlerhood was more negative for fathers with low CORT. In contrast to mothers, higher postpartum CORT in fathers was associated with lower caregiving quality in toddlerhood. These findings proved robust after applying the Benjamini-Hochberg procedure to control for false discovery rate. Our findings indicate that CORT and T during the perinatal period can forecast caregiving quality in both mothers and fathers. Moreover, our results provided evidence for the dual-hormone hypothesis, but only in fathers. These findings contribute to our growing understanding on how endocrine measures explain individual differences in caregiving quality in mothers and fathers.

Reproductive history, as measured by parity, age at first birth and sex of offspring, and cancer-specific survival after a haematological malignancy

BACKGROUND

Overall, women have better cancer-specific survival than men following haematological malignancies. The effect of reproductive factors on prognosis in women remains unknown and population-based studies are needed.

MATERIAL AND METHODS

A nationwide cohort of 21,237 Swedish women with a recorded haematological malignancy at ages 18-69 years was identified in the Swedish Cancer Register 1970-2018. Pre-diagnosis childbirths for each woman were linked to the Swedish Multigeneration Register. Net survival and excess hazard ratios for parity, age at first birth, time since the latest birth, and sex of offspring were estimated using flexible parametric models adjusted for age, year, and educational level.

RESULTS

In unadjusted analyses, parity (p = 0.0012) and high age at first birth (p < 0.0001) were associated with better survival. After co-adjustments for reproductive factors and confounders, the associations were attenuated. The adjusted association with parity was mainly observed among women aged above 40 years at diagnosis (p = 0.0033). The associations with reproductive factors were non-significant across subtypes of haematological malignancy. There was a tendency of higher excess mortality for an increasing number of boys compared to girls, although only significant for women with three or more children (p = 0.0126).

CONCLUSION

Reproductive factors were in part associated with survival following diagnosis of a haematological malignancy. However, the effect sizes were small with inconsistent association patterns, and thus reproductive factors may only partly contribute to the survival advantage of women over men.

Interoception is associated with anxiety and depression in pregnant women: A pilot study

Pregnancy and postpartum are periods in which women develop psychosocially. However, becoming a mother is stressful, and mood disorders related to anxiety and depression often develop. In recent years, research on interoception-sensations related to the body's internal physiological state-has attracted attention. Interoception has multifaceted characteristics. It involves directly perceiving information in the body while also inferring and evaluating it. In this study, we examined interoception, anxiety, and depression in Japanese pregnant women. Empirical examinations and questionnaire surveys were used to measure interoception in 32 pregnant women not at high risk of pregnancy. A Japanese adaption of the Multidimensional Assessment of Interoceptive Awareness was used to measure interoceptive sensibility, and a heartbeat counting task performance was used to measure interoceptive accuracy. Anxiety and depression were measured using the Japanese versions of the State-Trait Anxiety Inventory and the Edinburgh Postnatal Depression Scale, respectively. A correlation analysis was performed between interoception, anxiety and depression and between differences between sensibility and accuracy of interoception, anxiety and depression. We revealed that interoceptive sensibility and differences between sensibility and accuracy of interoception were associated with anxiety. Based on results of this pilot study, it is necessary to investigate using longitudinal studies whether interoception might be an effective predictor tool for early detection of anxiety during pregnancy and postpartum.

Motherhood and theory of mind: increased activation in the posterior cingulate cortex and insulae

Despite growing evidence on effects of parenthood on social understanding, little is known about the influence of parenthood on theory of mind (ToM), the capacity to infer mental and affective states of others. It is also unclear whether any possible effects of parenthood on ToM would generalise to inferring states of adults or are specific to children. We investigated neural activation in mothers and women without children while they predicted action intentions from child and adult faces. Region-of-interest analyses showed stronger activation in mothers in the bilateral posterior cingulate cortex, precuneus (ToM-related areas) and insulae (emotion-related areas). Whole-brain analyses revealed that mothers compared to non-mothers more strongly activated areas including the left angular gyrus and the ventral prefrontal cortex but less strongly activated the right supramarginal gyrus and the dorsal prefrontal cortex. These differences were not specific to child stimuli but occurred in response to both adult and child stimuli and might indicate that mothers and non-mothers employ different strategies to infer action intentions from affective faces. Whether these general differences in affective ToM between mothers and non-mothers are due to biological or experience-related changes should be subject of further investigation.

'That Time of the Month' - Investigating the Influence of the Menstrual Cycle and Oral Contraceptives on the Brain Using Magnetic Resonance Imaging

The stereotypic and oversimplified relationship between female sex hormones and undesirable behavior dates to the earliest days of human society, as already the ancient Greek word for the uterus, "hystera" indicated an aversive connection. Remaining and evolving throughout the centuries, transcending across cultures and various aspects of everyday life, its perception was only recently reframed. Contemporarily, the complex interaction of hormonal phases (i. e., the menstrual cycle), hormonal medication (i. e., oral contraceptives), women's psychological well-being, and behavior is the subject of multifaceted and more reflected discussions. A driving force of this ongoing paradigm shift was the introduction of this highly interesting and important topic into the realm of scientific research. This refers to neuroscientific research as it enables a multimodal approach combining aspects of physiology, medicine, and psychology. Here a growing body of literature points towards significant alterations of both brain function, such as lateralization of cognitive functions, and structure, such as gray matter concentrations, due to fluctuations and changes in hormonal levels. This especially concerns female sex hormones. However, the more research is conducted within this field, the less reliable these observations and derived insights appear. This may be due to two particular factors: measurement inconsistencies and diverse hormonal phases accompanied by interindividual differences. The first factor refers to the prominent unreliability of one of the primarily utilized neuroscientific research instruments: functional magnetic resonance imaging (fMRI). This unreliability is seemingly present in paradigms and analyses, and their interplay, and is additionally affected by the second factor. In more detail, hormonal phases and levels further influence neuroscientific results obtained through fMRI as outcomes vary drastically across different cycle phases and medication. This resulting vast uncertainty thus tremendously hinders the further advancement of our understanding of how female sex hormones might alter brain structure and function and, ultimately, behavior.This review summarizes parts of the current state of research and outlines the essential requirements to further investigate and understand the female brain's underlying physiological and anatomical features.

Processing children's faces in the parental brain: A meta-analysis of ERP studies

Event-related potentials (ERPs) are an excellent tool for investigating parental neural responses to child stimuli. Using meta-analysis, we quantified the results of available studies reporting N170 or LPP/P3 ERP responses to children's faces, targeting three questions: 1) Do parents and non-parents differ in ERP responses to child faces? 2) Are parental ERP responses larger to own vs. unfamiliar child faces? 3) Are parental ERP responses to child faces associated with indicators of parenting quality, such as observed parental sensitivity? Across 23 studies (N = 1035), key findings showed 1) larger N170 amplitudes to child faces in parents than in non-parents (r = 0.19), 2) larger LPP/P3 responses to own vs. unfamiliar child faces in parents (r = 0.19), and 3) positive associations between parental LPP/P3 responses to child faces and parenting quality outcomes (r = 0.15). These results encourage further research particularly with the LPP/P3 to assess attentional-motivational processes of parenting, but also highlight the need for larger samples and more systematic assessments of associations between ERPs and parenting.

A Critical Review and Meta-Analysis of Impacts of Per- and Polyfluorinated Substances on the Brain and Behavior

Per- and polyfluoroalkyl substances (PFAS) are a class of structurally diverse synthetic organic chemicals that are chemically stable, resistant to degradation, and persistent in terrestrial and aquatic environments. Widespread use of PFAS in industrial processing and manufacturing over the last 70 years has led to global contamination of built and natural environments. The brain is a lipid rich and highly vascularized organ composed of long-lived neurons and glial cells that are especially vulnerable to the impacts of persistent and lipophilic toxicants. Generally, PFAS partition to protein-rich tissues of the body, primarily the liver and blood, but are also detected in the brains of humans, wildlife, and laboratory animals. Here we review factors impacting the absorption, distribution, and accumulation of PFAS in the brain, and currently available evidence for neurotoxic impacts defined by disruption of neurochemical, neurophysiological, and behavioral endpoints. Emphasis is placed on the neurotoxic potential of exposures during critical periods of development and in sensitive populations, and factors that may exacerbate neurotoxicity of PFAS. While limitations and inconsistencies across studies exist, the available body of evidence suggests that the neurobehavioral impacts of long-chain PFAS exposures during development are more pronounced than impacts resulting from exposure during adulthood. There is a paucity of experimental studies evaluating neurobehavioral and molecular mechanisms of short-chain PFAS, and even greater data gaps in the analysis of neurotoxicity for PFAS outside of the perfluoroalkyl acids. Whereas most experimental studies were focused on acute and subchronic impacts resulting from high dose exposures to a single PFAS congener, more realistic exposures for humans and wildlife are mixtures exposures that are relatively chronic and low dose in nature. Our evaluation of the available human epidemiological, experimental, and wildlife data also indicates heightened accumulation of perfluoroalkyl acids in the brain after environmental exposure, in comparison to the experimental studies. These findings highlight the need for additional experimental analysis of neurodevelopmental impacts of environmentally relevant concentrations and complex mixtures of PFAS.

Increased child‐evoked activation in the precuneus during facial affect recognition in mothers

Successful parenting requires constant inferring of affective states. Especially vital is the correct identification of facial affect. Previous studies have shown that infant faces are processed preferentially compared to adult faces both on the behavioural and the neural level. This study specifically investigates the child‐evoked neural responses to affective faces and their modulation by motherhood and attention to affect. To do so, we used a paradigm to measure neural responses during both explicit and implicit facial affect recognition (FAR) in mothers and non‐mothers using child and adult faces. Increased activation to child compared to adult faces was found for mothers and non‐mothers in face processing areas (bilateral fusiform gyri) and areas associated with social understanding (bilateral insulae and medial superior frontal gyrus) when pooling implicit and explicit affect recognition. Furthermore, this child‐evoked activation was modulated by motherhood with an increase in mothers compared to non‐mothers in the left precuneus. Additionally, explicitly recognising the affect increased child‐evoked activation in the medial superior frontal gyrus in both mothers and non‐mothers. These results suggest preferential treatment of affective child over adult faces, modulated by motherhood and attention to affect.

Parenting in the Context of the Child: Genetic and Social Processes

The focus on the role of parenting in child development has a long-standing history. When measures of parenting precede changes in child development, researchers typically infer a causal role of parenting practices and attitudes on child development. However, this research is usually conducted with parents raising their own biological offspring. Such research designs cannot account for the effects of genes that are common to parents and children, nor for genetically influenced traits in children that influence how they are parented and how parenting affects them. The aim of this monograph is to provide a clearer view of parenting by synthesizing findings from the Early Growth and Development Study (EGDS). EGDS is a longitudinal study of adopted children, their birth parents, and their rearing parents studied across infancy and childhood. Families (N = 561) were recruited in the United States through adoption agencies between 2000 and 2010. Data collection began when adoptees were 9 months old (males = 57.2%; White 54.5%, Black 13.2%, Hispanic/Latinx 13.4%, Multiracial 17.8%, other 1.1%). The median child age at adoption placement was 2 days (M = 5.58, SD = 11.32). Adoptive parents were predominantly in their 30s, White, and coming from upper-middle- or upper-class backgrounds with high educational attainment (a mode at 4-year college or graduate degree). Most adoptive parents were heterosexual couples, and were married at the beginning of the project. The birth parent sample was more racially and ethnically diverse, but the majority (70%) were White. At the beginning of the study, most birth mothers and fathers were in their 20s, with a mode of educational attainment at high school degree, and few of them were married. We have been following these family members over time, assessing their genetic influences, prenatal environment, rearing environment, and child development. Controlling for effects of genes common to parents and children, we confirmed some previously reported associations between parenting, parent psychopathology, and marital adjustment in relation to child problematic and prosocial behavior. We also observed effects of children's heritable characteristics, characteristics thought to be transmitted from parent to child by genetic means, on their parents and how those effects contributed to subsequent child development. For example, we found that genetically influenced child impulsivity and social withdrawal both elicited harsh parenting, whereas a genetically influenced sunny disposition elicited parental warmth. We found numerous instances of children's genetically influenced characteristics that enhanced positive parental influences on child development or that protected them from harsh parenting. Integrating our findings, we propose a new, genetically informed process model of parenting. We posit that parents implicitly or explicitly detect genetically influenced liabilities and assets in their children. We also suggest future research into factors such as marital adjustment, that favor parents responding with appropriate protection or enhancement. Our findings illustrate a productive use of genetic information in prevention research: helping parents respond effectively to a profile of child strengths and challenges rather than using genetic information simply to identify some children unresponsive to current preventive interventions.

Perinatal depression is associated with a higher polygenic risk for major depressive disorder than non-perinatal depression

BACKGROUND

Distinctions between major depressive disorder (MDD) and perinatal depression (PND) reflect varying views of PND, from a unique etiological subtype of MDD to an MDD episode that happens to coincide with childbirth. This case-control study investigated genetic differences between PND and MDD outside the perinatal period (non-perinatal depression or NPD).

METHODS

We conducted a genome-wide association study using PND cases (Edinburgh Postnatal Depression Scale score ≥ 13) from the Australian Genetics of Depression Study 2018 data (n = 3804) and screened controls (n = 6134). Results of gene-set enrichment analysis were compared with those of women with non-PND. For six psychiatric disorders/traits, genetic correlations with PND were evaluated, and logistic regression analysis reported polygenic score (PGS) association with both PND and NPD.

RESULTS

Genes differentially expressed in ovarian tissue were significantly enriched (stdBeta = 0.07, p = 3.3e-04), but were not found to be associated with NPD. The genetic correlation between PND and MDD was 0.93 (SE = 0.07; p = 3.5e-38). Compared with controls, PGS for MDD are higher for PND cases (odds ratio [OR] = 1.8, confidence interval [CI] = [1.7-1.8], p = 9.5e-140) than for NPD cases (OR = 1.6, CI = [1.5-1.7], p = 1.2e-49). Highest risk is for those reporting both antenatal and postnatal depression, irrespective of prior MDD history.

CONCLUSIONS

PND has a high genetic overlap with MDD, but points of distinction focus on differential expression in ovarian tissue and higher MDD PGS, particularly for women experiencing both antenatal and postpartum PND.

Epigenetic Clock Deceleration and Maternal Reproductive Efforts: Associations With Increasing Gray Matter Volume of the Precuneus

Reproductive efforts, such as pregnancy, delivery, and interaction with children, make maternal brains optimized for child-rearing. However, extensive studies in non-human species revealed a tradeoff between reproductive effort and life expectancy. In humans, large demographic studies have shown that this is the case for the most part; however, molecular marker studies regarding aging remain controversial. There are no studies simultaneously evaluating the relationship between reproductive effort, aging, and brain structures. We therefore examined the associations between reproductive efforts (parity status, number of deliveries, motherhood period, and cumulative motherhood period), DNA methylation age (mAge) acceleration (based on Horvath’s multi-tissue clock and the skin & blood clock), and the regional gray matter volumes (obtained through brain magnetic resonance imaging (MRI) using voxel-based morphometry) in 51 mothers aged 27–46 years of children in early childhood. We found that increasing reproductive efforts were significantly associated with decelerated aging in mothers with one to four children, even after adjusting for the confounding effects in the multiple linear regression models. We also found that the left precuneus gray matter volume was larger as deceleration of aging occurred; increasing left precuneus gray matter volume, on the other hand, mediates the relationship between parity status and mAge deceleration. Our findings suggest that mothers of children in early childhood, who have had less than four children, may benefit from deceleration of aging mediated via structural changes in the precuneus.

Highlights regarding prolactin in the dentate gyrus and hippocampus

Prolactin (PRL) is a pituitary hormone that has been typically related to lactogenesis in mammals. However, it has been described over 300 roles in the organism of vertebrae and its relationship with the central nervous system (CNS) is yet to be clarified. Mainly secreted by the pituitary gland, the source of prolactin in the CNS remains unclear, where some experiments suggest active transport via an unknown carrier or, on the contrary, PRL being synthesized on the brain. So far, it seems to be involved with neurogenesis, neuroprotection, maternal behavior and cognitive processes in the hippocampus and dentate gyrus, among other regions.

Less can be more: Fine tuning the maternal brain

PAWLUSKI, J.L., Hoekzema, E., Leuner, B., and Lonstein, J.S. Less can be more: Fine tuning the maternal brain. NEUROSCI BIOBEHAV REV (129) XXX-XXX, 2022. Plasticity in the female brain across the lifespan has recently become a growing field of scientific inquiry. This has led to the understanding that the transition to motherhood is marked by some of the most significant changes in brain plasticity in the adult female brain. Perhaps unexpectedly, plasticity occurring in the maternal brain often involves a decrease in brain volume, neurogenesis and glial cell density that presumably optimizes caregiving and other postpartum behaviors. This review summarizes what we know of the 'fine-tuning' of the female brain that accompanies motherhood and highlights the implications of these changes for maternal neurobehavioral health. The first part of the review summarizes structural and functional brain changes in humans during pregnancy and postpartum period with the remainder of the review focusing on neural and glial plasticity during the peripartum period in animal models. The aim of this review is to provide a clear understanding of when 'less is more' in maternal brain plasticity and where future research can focus to improve our understanding of the unique brain plasticity occurring during matrescence.

Pregnancy and brain architecture: Associations with hormones, cognition and affect

Sex hormones such as estradiol (E2) have long-lasting influence on brain architecture. Recent studies indicate further structural changes during hormonal transition periods including pregnancy, when women experience the greatest increase in sex hormone levels across their life span. In the present study, three groups of women (n = 44) with different levels of E2 underwent structural magnetic resonance imaging: (1) first-time pregnant women (n = 13, 'extreme E2 group'); (2), nulliparous, naturally cycling women who received 12 mg of E2 valerate (n = 16, 'high E2 group'); and (3) nulliparous, naturally cycling women receiving a placebo and hence low E2 (n = 15, 'low E2 group'). Blood samples were taken to assess hormonal levels. Moreover, parameters for cognition, emotion regulation and affect were assessed. On the neuronal level, the extreme E2 compared to the high E2 group showed a reduced gray matter volume in the left putamen. However, no significant differences were found between the low vs. high E2 groups, nor between the low E2 and extreme E2 groups. Cognitive performance was reduced in the extreme E2 group, although a positive affect was increased compared to the high E2 and low E2 groups. Furthermore, regression analyses revealed several associations between cognition, subjective measures of affect, emotion regulation and gray matter volume. A volume reduction of the left putamen during pregnancy further supports the notion that the female brain is shaped by hormonal transition phases, possibly preparing women for their future roles (e.g., pregnant women for their role as mothers).

Pregnancy-induced brain MRI changes in women with multiple sclerosis

BACKGROUND

The effect of pregnancy on brain changes and radiological disease activity in women with multiple sclerosis (MS) is not well understood.

AIMS

To describe the dynamic of lesion activity and brain volume changes during the pregnancy and postpartum periods.

METHODS

This observational study of 62 women with relapsing-remitting MS included MRI (221 scans) as well as clinical visits at baseline (<24 and >6 months before), prepregnancy (<6 months before), postpartum (<3 months after), and the follow-up (>12 and <24 months after delivery) period.

RESULTS

The majority of women had a mild disability and a short disease duration (median 5.5 years). Eighteen (29.0%) women had a relapse during the year preceding pregnancy onset, 9 (14.5%) during pregnancy, and 20 (32.3%) in the year following delivery. Disability status remained unchanged during follow-up. Women in the postpartum period (n=62) had higher T2 lesion volume (median: 0.94 ml vs. 1.18 ml), greater annualized T2 lesion volume increase (0.0 ml vs. 0.23 ml), lower brain parenchymal fraction (86.4% vs. 85.6%) and greater annualized brain volume loss (-0.16% vs. -1.74%) compared with the prepregnancy period (all p<0.001). At 12-24 months after delivery women (n=41) had higher T2 lesion volume (1.0 ml vs. 1.16 ml) and lower brain parenchymal fraction (86.5% vs. 86.0%) compared to the prepregnancy period (both p<0.001).

CONCLUSIONS

The postpartum period was associated with an increase in T2 lesion volume and accelerated brain volume loss in a considerable proportion of women. This should be considered in treatment decision-making and designing clinical trials.

Long-term association of pregnancy and maternal brain structure: the Rotterdam Study

The peripartum period is the highest risk interval for the onset or exacerbation of psychiatric illness in women’s lives. Notably, pregnancy and childbirth have been associated with short-term structural and functional changes in the maternal human brain. Yet the long-term effects of pregnancy on maternal brain structure remain unknown. We investigated a large population-based cohort to examine the association between parity and brain structure. In total, 2,835 women (mean age 65.2 years; all free from dementia, stroke, and cortical brain infarcts) from the Rotterdam Study underwent magnetic resonance imaging (1.5 T) between 2005 and 2015. Associations of parity with global and lobar brain tissue volumes, white matter microstructure, and markers of vascular brain disease were examined using regression models. We found that parity was associated with a larger global gray matter volume (β = 0.14, 95% CI = 0.09–0.19), a finding that persisted following adjustment for sociodemographic factors. A non-significant dose-dependent relationship was observed between a higher number of childbirths and larger gray matter volume. The gray matter volume association with parity was globally proportional across lobes. No associations were found regarding white matter volume or integrity, nor with markers of cerebral small vessel disease. The current findings suggest that pregnancy and childbirth are associated with robust long-term changes in brain structure involving a larger global gray matter volume that persists for decades. Future studies are warranted to further investigate the mechanism and physiological relevance of these differences in brain morphology.

Evidence for cognitive plasticity during pregnancy via enhanced learning and memory

Human and animal neuroscience studies support the view that plastic shifts occur in the brain during pregnancy that support the emergence of new maternal behaviours. The idea of adaptive plasticity in pregnancy is at odds with the notion of "baby brain", in which pregnant women describe the onset of forgetfulness. While inconsistent evidence for memory deficits during pregnancy has been reported, few studies have investigated spatial associative memory (which is consistently enhanced in studies of pregnant rodents). Moreover, most studies assess domain-general stimuli, which might miss adaptations specific to parent-relevant stimuli. In the present study, we examined the retention of spatial associative memory for parenting-relevant and non-parenting-relevant stimuli across 4-weeks in a sample of women in their third trimester of pregnancy, and compared their performance to a sample of never pregnant women. We demonstrated that relative to never pregnant women, pregnant women exhibited enhanced long-term retention of object-scene-location associations (spatial associative memory), as well as better initial learning about parenting-relevant, relative to non-parenting-relevant, stimuli. Thus, similar to studies in rodents, cognitive improvements were seen during pregnancy in humans, and those improvements were specific to the domain of spatial associative retention, and in the recognition of stimuli relevant to parenting.

Recent Neuroscience Advances in Human Parenting

The transition to parenthood entails brain adaptations to the demands of caring for a newborn. This chapter reviews recent neuroscience findings on human parenting, focusing on neuroimaging studies. First, we describe the brain circuits underlying human maternal behavior, which comprise ancient subcortical circuits and more sophisticated cortical regions. Then, we present the short-term and long-term functional and structural brain adaptations that characterize the transition to motherhood, discuss the long-term effects of parenthood on the brain, and propose several underlying neural mechanisms. We also review neuroimaging findings in biological fathers and alloparents (such as other relatives or adoptive parents), who engage in parenting without directly experiencing pregnancy or childbirth. Finally, we describe perinatal mental illnesses and discuss the neural responses associated with such disorders. To date, studies indicate that parenthood is a period of enhanced brain plasticity within brain areas critical for cognitive and social processing and that both parenting experience and gestational-related factors can prime such plasticity.

Olfaction in pregnancy: systematic review and meta-analysis

Little attention has been paid to olfactory changes during pregnancy with contemporary studies limited in number and sample size. We examined whether pregnancy is associated with differences in olfactory performance and if there were any specific gestational ages at which these differences occur through a comprehensive systematic review and meta-analysis of the current literature. An initial electronic database search identified 234 citations, which were screened at the abstract level. Twenty-three citations were germane for full-text review, and 13 met criteria for inclusion. Our review assessed 5 olfactory measures of interest: odor identification (n = 11 articles), threshold (n = 8), discrimination (n = 5), hedonics (n = 6), and intensity (n = 5). Nine of these 13 studies contained sufficient data for meta-analysis, and these studies included a total of 523 pregnant women and 365 non-pregnant controls. Despite previous subjective and objective reports of odor intolerances and odor hypersensitivity, we did not find any significant differences between pregnant and non-pregnant women in odor discrimination, thresholds, or hedonics. However, meta-analysis of 506 cases and 333 controls showed worse odor identification in pregnant women compared to controls in a random-effects model. Thus, we demonstrate worse performance at odor identification during pregnancy. In this review, we discuss the current evidence (and lack thereof) regarding olfaction in pregnancy as well as highlight current knowledge gaps in this field.

Is Brain-Derived Neurotropic Factor Methylation Involved in the Association Between Prenatal Stress and Maternal Postnatal Anxiety During the COVID-19 Pandemic?

BACKGROUND

The COVID-19 pandemic is a collective trauma that may expose susceptible individuals to high levels of stress. Pregnant women represent a high-risk population, considering that pregnancy is a period of heightened neuroplasticity and susceptibility to stress through epigenetic mechanisms. Previous studies showed that the methylation status of the BDNF gene is linked with prenatal stress exposure. The goals of this study were (a) to assess the association between pandemic-related stress and postnatal anxiety and (b) to investigate the potential role of maternal BDNF methylation as a significant mediator of this association.

METHODS

In the present study, we report data on the association among pandemic-related stress during pregnancy, maternal BDNF methylation, and postnatal anxiety symptoms. Pandemic-related stress and postnatal anxiety were assessed through self-report instruments. BDNF methylation was estimated in 11 CpG sites in DNA from mothers' buccal cells. Complete data were available from 108 mothers.

RESULTS

Results showed that pandemic-related stress was associated with an increased risk of postnatal anxiety, r = 0.20, p < 0.05. CpG-specific BDNF methylation was significantly associated with both prenatal pandemic-related stress, r = 0.21, p < 0.05, and postnatal maternal anxious symptoms, r = 0.25, p = 0.01. Moreover, a complete mediation by the BDNF CpG6 methylation emerged between pandemic-related stress during pregnancy and postnatal maternal anxiety, ACME = 0.66, p < 0.05.

CONCLUSION

These findings suggest that BDNF epigenetic regulation by pandemic-related stress might contribute to increase the risk of anxiety in mothers. Policymakers should prioritize the promotion of health and wellbeing in pregnant women and mothers during the present healthcare emergency.

Longitudinal Study of Maternal Beliefs About Infant Crying During the Postpartum Period: Interplay With Infant’s Temperament

Infant crying is an important signal for their survival and development, and maternal beliefs about crying predict responsiveness to crying. Most studies have considered caregivers’ reactions to crying to be fixed, and it is unclear how they change with their caregiving experience. Additionally, it has recently been suggested that there is a bidirectional relationship between changes in mothers’ beliefs about crying and infants’ temperament. This study examined that relationship using a longitudinal study design. Maternal beliefs about crying and infant temperament of 339 Asian first-time mothers (mean age = 28.7 years, SD = 4.1) were measured at 1-month intervals over 4 months. There were 289 participants in Wave 2, 240 in Wave 3, and 164 in Wave 4. Prior to the main survey, we conducted a pre-survey to confirm the reliability and validity of the Japanese version of the Infant Crying Questionnaire. The results showed that parent-oriented beliefs, which focus on the caregiver rather than the crying infant, increased in mothers who had infants aged 3 months or older at Wave 1. We also found that the process of change in maternal beliefs was not uniform, and that infants high on surgency predicted changes in maternal beliefs about infant crying. Longitudinal studies of caregivers’ changes, such as the present study, are expected to contribute to understanding the co-development of caregivers and infants.

Effects of Cognitive Nursing Combined with Continuous Nursing on Postpartum Mental State and Rehabilitation

Purpose

This study is aimed at exploring the effects of cognitive nursing combined with continuous nursing on postpartum mental state and rehabilitation.

Methods

Totally, 124 puerperas admitted to our hospital from January 2019 to January 2020 were selected and divided into a research group and a control group according to different nursing methods, with 62 cases in each group. The control group received routine care, while the research group received cognitive nursing combined with continuous nursing on this basis. The mental state, rehabilitation indicators, quality of life, incidence of complications, and nursing satisfaction were compared between the two groups after intervention.

Results

Before nursing, there was no statistically significant difference in the SAS and SDS scores between the two groups (P > 0.05); after intervention, the SAS and SDS scores of the two groups were significantly reduced, and those of the research group were lower than those of the control group (P < 0.05). After intervention, the time of the first breastfeeding, duration of lochia rubra, length of hospital stay, and score of uterine contraction pain of the research group were lower than those of the control group (P < 0.05); the psychological function, physical function, material life, and social function scores of the research group were higher than those of the control group (P < 0.05); the incidence of complications in the research group was 4.84%, lower than 20.97% in the control group (P < 0.05); the nursing satisfaction of the research group was 96.77%, which was significantly higher than 83.87% in the control group (P < 0.05).

Conclusions

Cognitive nursing combined with continuous nursing can effectively improve the mental state, shorten the length of hospital stay, increase the perceived well-being, and promote the physical rehabilitation in puerperas, which is worth promoting in clinical practice.

Postpartum Gray Matter Changes in the Auditory Cortex

After giving birth, a mother’s brain undergoes functional adaptations fostering the ability to properly respond to the needs of her newborn. Tuning into and understanding her baby’s crying is among the top skills required and executed in the early stages of motherhood. However, surprisingly little is known about potential changes in the anatomy of the maternal auditory cortex. Therefore, in this longitudinal study, we compared the brains of 14 healthy women between immediate postpartum (within 1–2 days of childbirth) and late postpartum (at 4–6 weeks after childbirth), focusing on areas of the primary, secondary, and higher auditory cortex. We observed significant volume increases within all auditory regions and subregions examined, which might reflect rapid adaptations of the mother’s brain in relation to reliably interpreting her newborn’s cries. There was also a trend for a larger postpartum increase within right-hemispheric regions compared to left-hemispheric regions that might be specifically linked to the ability to discern the pitch, sound, and volume of a baby’s crying. Follow-up research is warranted to replicate these findings and evaluate their current interpretation.

Association Between Perceived Stress and Prenatal Depressive Symptoms: Moderating Effect of Social Support

Purpose

Prenatal depressive symptoms are an important mental health problem during pregnancy. We aimed to explore the moderating role of social support on the association between perceived stress and prenatal depressive symptoms.

Materials and Methods

A cross-sectional study was conducted at an obstetrics clinic. A total of 1846 women completed a self-administered questionnaire, with a response rate of 91.8%.

Results

Of the 1846 participants, 28.2% reported prenatal depressive symptoms (Edinburgh postnatal depression scale score ≥ 9). After adjusting for demographic characteristics, gestational age, exercise, and passive smoking, both perceived stress (adjusted odds ratio (AOR): 1.210, 95% confidence interval (CI): 1.178–1.242) and social support (AOR: 0.950, 95% CI: 0.932–0.968) were associated with prenatal depressive symptoms. Moreover, social support had a moderating effect on the association between perceived stress and prenatal depressive symptoms (p < 0.001), and pregnant women with low social support were more likely to be affected by stress and experience prenatal depressive symptoms.

Conclusion

Our study suggests that higher social support reduces the impact of stress on pregnant women, which in turn, decreases the risk of prenatal depressive symptoms. Therefore, interventions aimed at improving social support should be considered for the prevention and treatment of prenatal depressive symptoms.

Characterizing the Brain Structural Adaptations Across the Motherhood Transition

Women that become mothers face notable physiological adaptations during this life-period. Neuroimaging studies of the last decade have provided grounded evidence that women's brains structurally change across the transition into motherhood. The characterization of this brain remodeling is currently in its early years of research. The current article reviews this scientific field by focusing on our longitudinal (pre-to-post pregnancy) Magnetic Resonance Imaging (MRI) studies in first-time parents and other longitudinal and cross-sectional studies of parents. We present the questions that are currently being answered by the parental brain literature and point out those that have not yet been explored. We also highlight potential confounding variables that need to be considered when analyzing and interpreting brain changes observed during motherhood.

Hypothalamus volume in men: Investigating associations with paternal status, self-reported caregiving beliefs, and adult attachment style

Most studies on mammalian caregiving and attachment focused on the mother-child relationship, particularly in humans. Yet, changing societal roles of male caregivers have highlighted the necessity for research with fathers.We examined the volume of the hypothalamus, an important subcortical brain area for caregiving and attachment, in N = 50 fathering (child age 5-6 years) and N = 45 non-fathering men using a novel technique to identify the hypothalamus in 3T MRI. We furthermore employed three self-report measures to assess interindividual differences in adult attachment style across all men and caregiving beliefs in fathers.While we did not observe any significant difference in hypothalamus volume between fathers and non-fathers or associations between hypothalamus volume and self-reported adult attachment style across all men, self-reported caregiving beliefs were positively related to total hypothalamus volume in fathers. A follow-up analysis showed that fathers' self-reported belief that a father's role is important to child development was specifically related to tuberal hypothalamus volume, while self-reported enjoyment of spending time with the child was not associated with sub-regional hypothalamus volume.Together, these findings suggest that interindividual variability in self-reported caregiving beliefs in fathers is related to brain structure, warranting further research.

Hormones and neuroplasticity: A lifetime of adaptive responses

Major life transitions often co-occur with significant fluctuations in hormones that modulate the central nervous system. These hormones enact neuroplastic mechanisms that prepare an organism to respond to novel environmental conditions and/or previously unencountered cognitive, emotional, and/or behavioral demands. In this review, we will explore several examples of how hormones mediate neuroplastic changes in order to produce adaptive responses, particularly during transitions in life stages. First, we will explore hormonal influences on social recognition in both males and females as they transition to sexual maturity. Next, we will probe the role of hormones in mediating the transitions to motherhood and fatherhood, respectively. Finally, we will survey the long-term impact of reproductive experience on neuroplasticity in females, including potential protective effects and risk factors associated with reproductive experience in mid-life and beyond. Ultimately, a more complete understanding of how hormones influence neuroplasticity throughout the lifespan, beyond development, is necessary for understanding how individuals respond to life changes in adaptive ways.

Exploring the sex and gender correlates of cognitive sex differences

The correlates of cognitive sex differences are yet to be fully understood. Many biological and psychosocial factors modulate these cognitive abilities leading to mixed results in the scientific literature. The current study aims to explore the different parameters potentially influencing cognitive abilities acting in synergy. Sex and gender correlates of cognitive functioning were assessed in a sample of individuals ages 18 to 45 years (N = 87) from diverse sexual orientations. Sex hormones were assessed via saliva samples at four timepoints throughout the testing. Gender roles, sexual orientation and socio-demographics were measured via self-report questionnaires. Participants completed mental rotation and verbal fluency tasks. Men performed better than women at mental rotation, while no significant difference was found for verbal fluency. Significant positive associations were observed between estradiol and word fluency for the naturally cycling women compared to the women using oral contraception. While controlling for sex hormones, a significant interaction effect of sex by gender roles was identified for mental rotation among masculine women. These exploratory results suggest an effect principally driven by sex and sex hormones on cognitive performance that will need to be furthered with larger studies.

Lactation is not required for maintaining maternal care and active coping responses in chronically stressed postpartum rats: Interactions between nursing demand and chronic variable stress

Women who do not breastfeed or discontinue breastfeeding early are more likely to develop postpartum depression (PPD) and stress is a significant risk factor for depression, including PPD. Using a rat model, we investigated whether the absence of nursing would increase the susceptibility to chronic stress-related behavioral and neural changes during the postpartum period. Adult female rats underwent thelectomy (thel; removal of teats), sham surgery, or no surgery (control) and were paired with males for breeding. All litters were rotated twice daily until postpartum day (PD) 26. Sham rats served as surrogates for thel litters, yielding a higher nursing demand for sham rats. Concurrently, rats received either no stress or chronic variable stress until PD 25. Rats were observed for maternal behaviors and tested in a series of tasks including open field, sucrose preference, and forced swim. We used immunohistochemistry (IHC) for doublecortin (DCX; to label immature neurons) or for mineralocorticoid receptor (MR). Contrary to our expectations, non-nursing thel rats were resistant to the effects of stress in all dependent measures. Our data indicate that even in chronic adverse conditions, nursing is not required for maintaining stable care to offspring or active coping responses in an acutely stressful task. We discuss the possible role of offspring contact and consider future directions for biomedical and clinical research. In rats with high nursing demand, however, chronic stress increased immobility, hippocampal neurogenesis, and MR expression (largely in opposition to the effects of stress in rats with typical nursing demand). We discuss these patterns in the context of energetics and allostatic load. This research highlights the complexity in relationships between stress, nursing, and neurobehavioral outcomes in the postpartum period and underscores the need for additional biomedical and clinical research geared toward optimizing treatments and interventions for women with PPD, regardless of breastfeeding status. SIGNIFICANCE STATEMENT: The goal of this research was to determine how the absence of nursing and higher nursing demand impact stress-coping behaviors and neural changes associated with chronic stress in order to disentangle the complex interplay of factors that contribute to psychological illness during the postpartum period.

Glutamate levels in the medial prefrontal cortex of healthy pregnant women compared to non-pregnant controls

Very little is known about maternal cerebral changes during pregnancy. Since there is an increased risk for major depression during pregnancy and postpartum, it is important to understand the structural and neurochemical changes that occur in the brain during pregnancy. Using proton magnetic resonance spectroscopy (¹H-MRS) (3 T field strength), glutamate (Glu) levels were measured in the medial prefrontal cortex (MPFC) of 21 healthy gravid subjects 2-3 weeks before their due date (6.74 ± 1.39), and in 14 non-pregnant healthy controls during their follicular phase (8.53 ± 1.55). Water quantified MPFC Glu levels were decreased in pregnant women (p < 0.01). We also observed a 13.9% decrease in percentage grey matter (%GM) (p < 0.01) in our MPFC voxel. As Glu is mostly found in GM, we repeated the statistical analysis after adjustment for %GM and found that the difference in Glu levels was no longer statistically significant when adjusted for %GM (p = 0.10). This investigation is the only systematic direct investigation of brain tissue composition and Glu levels in pregnant women. The main finding of this investigation is the decreased %GM in healthy pregnant women compared to non-pregnant women. These findings of decreased %GM in pregnancy may be responsible for the frequent complaints by pregnant women of cognitive difficulties also described as pregnesia.

In search of sex-related mediators of affective illness

Sex differences in the rates of affective disorders have been recognized for decades. Studies of physiologic sex-related differences in animals and humans, however, have generally yielded little in terms of explaining these differences. Furthermore, the significance of these findings is difficult to interpret given the dynamic, integrative, and highly context-dependent nature of human physiology. In this article, we provide an overview of the current literature on sex differences as they relate to mood disorders, organizing existing findings into five levels at which sex differences conceivably influence physiology relevant to affective states. These levels include the following: brain structure, network connectivity, signal transduction, transcription/translation, and epigenesis. We then evaluate the importance and limitations of this body of work, as well as offer perspectives on the future of research into sex differences. In creating this overview, we attempt to bring perspective to a body of research that is complex, poorly synthesized, and far from complete, as well as provide a theoretical framework for thinking about the role that sex differences ultimately play in affective regulation. Despite the overall gaps regarding both the underlying pathogenesis of affective illness and the role of sex-related factors in the development of affective disorders, it is evident that sex should be considered as an important contributor to alterations in neural function giving rise to susceptibility to and expression of depression.

Fathers' Involvement in Early Childcare is Associated with Amygdala Resting-State Connectivity

Becoming a parent requires new skills and frequent task switching during daily childcare. Little is known about the paternal brain during the transition to fatherhood. The present study examined intrinsic neuronal network connectivity in a group of first-time expectant and new fathers (total N = 131) using amygdala seed-based resting-state functional connectivity analysis. Furthermore, we examined the association between paternal involvement (i.e. hours spent in childcare and real-time push notifications on smartphone) and connectivity within the parental brain network in new fathers. There were no significant differences in functional connectivity between expectant and new fathers. However, results show that in new fathers, time spent in childcare was positively related to amygdala connectivity with the supramarginal gyrus, postcentral gyrus and the superior parietal lobule—all regions within the cognition/mentalizing network that have been associated with empathy and social cognition. Our results suggest that fathers’ time investment in childcare is related to connectivity networks in the parental brain.

The risk and protective factors of heightened prenatal anxiety and depression during the COVID-19 lockdown

While pregnant women are already at-risk for developing symptoms of anxiety and depression, this is heightened during the COVID-19 pandemic. We compared anxiety and depression symptoms, as indicators of psychological distress, before and during COVID-19, and investigated the role of partner, social network and healthcare support on COVID-19-related worries and consequently on psychological distress. A national survey, conducted during the first lockdown in The Netherlands, assessed COVID-19 experiences and psychological distress (N = 1421), whereas a comparison sample (N = 1439) was screened for psychological distress in 2017-2018. During COVID-19, the percentage of mothers scoring above the questionnaires' clinical cut-offs doubled for depression (6% and 12%) and anxiety (24% and 52%). Women reported increased partner support during COVID-19, compared to pre-pandemic, but decreased social and healthcare support. Higher support resulted in lower COVID-19-related worries, which in turn contributed to less psychological distress. Results suggest that a global pandemic exerts a heavy toll on pregnant women's mental health. Psychological distress was substantially higher during the pandemic than the pre-pandemic years. We identified a protective role of partner, social, and healthcare support, with important implications for the current and future crisis management. Whether increased psychological distress is transient or persistent, and whether and how it affects the future generation remains to be determined.

Understanding identification-based trust in the light of affiliative bonding: Meta-analytic neuroimaging evidence

Trust is vital for establishing social relationships and is a crucial precursor for affiliative bonds. Investigations explored the neuropsychological bases of trust separately (e.g., measured by the trust game) and affiliative bonding (e.g., measured by parental care, pair-bonding, or friendship). However, direct empirical support for the shared neural mechanisms between trust and affiliative bonding is missing. Here, we conducted a coordinate-based meta-analysis on functional magnetic resonance imaging studies on interpersonal trust and affiliative bonding using the activation likelihood estimation method. Our results demonstrated that decisions to trust strangers in repeated interactions (i.e., identification-based trust) engaged the ventral striatum (vSTR, part of the mesolimbic dopaminergic pathway), likely signaling the reward anticipation. Further, both feedbacks in repeated interactions and affiliative bonding engaged the dorsal striatum (dSTR, part of the nigrostriatal dopaminergic pathway), likely encoding learning dynamics. Our findings suggest that identification-based trust can be understood in the light of affiliative bonding, involving the mesocorticolimbic "reward" pathway (vSTR) and nigrostriatal "habit formation" pathway (dSTR) in building and sustaining social relationships.

Altered gray matter structural covariance networks in postpartum depression: a graph theoretical analysis

BACKGROUND

Postpartum depression (PPD) is a serious postpartum mental health problem worldwide. To date, minimal is known about the alteration of topographical organization in the brain structural covariance network of patients with PPD. This study investigates the brain structural covariance networks of patients with PPD by using graph theoretical analysis.

METHODS

High-resolution 3D T1 structural images were acquired from 21 drug-naive patients with PPD and 18 healthy postpartum women. Cortical thickness was extracted from 64 brain regions to construct the whole-brain structural covariance networks by calculating the Pearson correlation coefficients, and their topological properties (e.g., small-worldness, efficiency, and nodal centrality) were analyzed by using graph theory. Nonparametric permutation tests were further used for group comparisons of topological metrics. A node was set as a hub if its betweenness centrality (BC) was at least two standard deviations higher than the mean nodal centrality. Network-based statistic (NBS) was used to determine the connected subnetwork.

RESULTS

The PPD and control groups showed small-worldness of group networks, but the small-world network was more evidently in the PPD group. Moreover, the PPD group showed increased network local efficiency and almost similar network global efficiency. However, the difference of the network metrics was not significant across the range of network densities. The hub nodes of the patients with PPD were right inferior parietal lobule (BC = 13.69) and right supramarginal gyrus (BC = 13.15), whereas those for the HCs were left cuneus (BC = 14.96), right caudal anterior-cingulate cortex (BC = 15.51), and right precuneus gyrus (BC = 15.74). NBS demonstrated two disrupted subnetworks that are present in PPD: the first subnetwork with decreased internodal connections is mainly involved in the cognitive-control network and visual network, and the second subnetwork with increased internodal connections is mainly involved in the default mode network, cognitive-control network and visual network.

CONCLUSIONS

This study demonstrates the alteration of topographical organization in the brain structural covariance network of patients with PPD, providing in sight on the notion that PPD could be characterized as a systems-level disorder.

Pregnancy-related hormones and COMT genotype: Associations with maternal working memory

Women experience different degrees of subjective cognitive changes during pregnancy. The exact mechanism underlying these changes is unknown, although endocrine alterations and genetics may be contributing factors. We investigated whether multiple pregnancy-related hormones were associated with working memory function assessed with the Digit Span Test (DST) in late pregnancy. Moreover, we examined whether the catechol-O-methyltransferase (COMT) genotype, previously related to working memory, was an effect modifier in this association. In this population-based panel study, we recorded psychiatric history, medication use, socio-demographic characteristics, and psychological well-being, gathered blood and saliva samples, and administered the DST at gestational weeks 35-39 (N = 216). We conducted multivariate linear regressions with DST as outcome, with different hormones and COMT genotype, adjusting for covariates including maternal age, BMI, education, depressive symptoms, and parity. We repeated these analyses excluding women with elevated depressive symptoms. Higher DST total scores were associated with increased free estradiol concentrations (B = 0.01, p = 0.03; B = 0.01, p = 0.02) in all participants and in participants without depressive symptoms, respectively, whereas DST forward was positively associated with free estradiol only in women without depressive symptoms (B = 0.01, p = 0.04). Lower total testosterone concentrations (B = -0.03, p = 0.01) enhanced DST backward performance in non-depressed women. Maternal higher education was significantly associated with the DST subscales in all participants. No significant differences emerged when considering the COMT genotype. Our results suggest differential associations of free estradiol and total testosterone levels with working memory function in late pregnancy.

Pregnancy leads to changes in the brain functional network: a connectome analysis

Pregnancy leads to long-lasting changes in human brain structure; however, little is known regarding alterations in the topological organization of functional networks. In this study, we investigated the effect of pregnancy on human brain function networks. Resting-state fMRI data was collected from eighteen primiparous mothers and twenty-four nulliparous control women of similar age, education level and body mass index (BMI). The functional brain network and topological properties were calculated by using GRETNA toolbox. The demographic data differences between two groups were computed by the independent two sample t-test. We tested group differences in network metrics' area under curve (AUC) using non-parametric permutation test of 1,000 permutations and corrected for false discovery rate (FDR). Differences in regional networks between groups were evaluated using non-parametric permutation tests by network-based statistical analysis (NBS). Compared with the nulliparous control women, a hub node changed from left inferior temporal gyrus to right precentral gyrus in primiparous mothers, while primiparous mothers showed enhanced network global efficiency (p = 0.247), enhanced local efficiency (p = 0.410), larger clustering coefficient (p = 0.410), but shorter characteristic path length (p = 0.247), smaller normalized clustering coefficient (p = 0.111), and shorter normalized characteristic path length (p = 0.705). Although both groups of functional networks have small-world property (σ > 1), the σ values of primiparous mothers were decreased significantly. NBS evaluation showed the majority of altered connected sub-network in the primiparous mothers occurred in the bilateral frontal lobe gyrus (p < 0.05). Altered functional network metrics and an abnormal sub-network were found in primiparous mothers, suggested that pregnancy may lead to changes in the brain functional network.

Three kinds of caesarean sections: the foetal/neonatal perspective

In the age of hospital births, it is commonplace to contrast the vaginal route and the abdominal route as the basic classification. From the "point of view" of the foetus/neonate, we provide reasons to contrast "birth without labour" (that is birth by pre-labour caesarean section) and all the other vaginal and abdominal modes of birth. From a great diversity of theoretical reasons, one can anticipate that babies born by pre-labour caesarean sections are different from the others. We also provide reasons to popularize the concepts of "in labour non-emergency caesarean sections" and "planned in-labour caesarean sections".

Maternal perinatal anxiety and neural responding to infant affective signals: Insights, challenges, and a road map for neuroimaging research

Anxiety symptoms are common among women during pregnancy and the postpartum period, potentially having detrimental effects on both mother and child's well-being. Perinatal maternal anxiety interferes with a core facet of adaptive caregiving: mothers' sensitive responsiveness to infant affective communicative 'cues.' This review summarizes the current research on the neural correlates of maternal processing of infant cues in the presence of perinatal anxiety, outlines its limitations, and offers next steps to advance future research. Functional neuroimaging studies examining the neural circuitry involved in, and electrophysiological studies examining the temporal dynamics of, processing infant cues during pregnancy and postpartum are reviewed. Studies have generally indicated mixed findings, although emerging themes suggest that anxiety may be implicated in several stages of processing infant cues- detection, interpretation, and reaction- contingent upon cue valence. Limitations include inconsistent designs, lack of differentiation between anxiety and depression symptoms, and limited consideration of parenting-specific (versus domain-general) anxiety. Future studies should incorporate longitudinal investigation of multiple levels of analysis spanning neural, cognitive, and observed aspects of sensitive caregiving.

The brain oxytocin and corticotropin-releasing factor systems in grieving mothers: What we know and what we need to learn

The bond between a mother and her child is the strongest bond in nature. Consequently, the loss of a child is one of the most stressful and traumatic life events that causes Prolonged Grief Disorder in up to 94 % of bereaved parents. While both parents are affected, mothers are of higher risk to develop mental health complications; yet, very little research has been done to understand the impact of the loss of a child, stillbirth and pregnancy loss on key neurobiological systems. The emotional impact of losing a child, e.g., Prolonged Grief Disorder, is likely accompanied by dysregulations in neural systems important for mental health. Among those are the neuropeptides contributing to attachment and stress processing. In this review, we present evidence for the involvement of the brain oxytocin (OXT) and corticotropin-releasing factor (CRF) systems, which both play a role in maternal behavior and the stress response, in the neurobiology of grief in mothers from a behavioral and molecular point of view. We will draw conclusions from reviewing relevant animal and human studies. However, the paucity of research on the tragic end to an integral bond in a female's life calls for the need and responsibility to conduct further studies on mothers experiencing the loss of a child both in the clinic and in appropriate animal models.

A history of previous childbirths is linked to women's white matter brain age in midlife and older age

Maternal brain adaptations occur in response to pregnancy, but little is known about how parity impacts white matter and white matter ageing trajectories later in life. Utilising global and regional brain age prediction based on multi-shell diffusion-weighted imaging data, we investigated the association between previous childbirths and white matter brain age in 8,895 women in the UK Biobank cohort (age range = 54-81 years). The results showed that number of previous childbirths was negatively associated with white matter brain age, potentially indicating a protective effect of parity on white matter later in life. Both global white matter and grey matter brain age estimates showed unique contributions to the association with previous childbirths, suggesting partly independent processes. Corpus callosum contributed uniquely to the global white matter association with previous childbirths, and showed a stronger relationship relative to several other tracts. While our findings demonstrate a link between reproductive history and brain white matter characteristics later in life, longitudinal studies are required to establish causality and determine how parity may influence women's white matter trajectories across the lifespan.

Parenting and addictions: Current insights from human neuroscience

Purpose

A growing body of human research has documented associations between the maternal brain and maternal substance use and addictions. This neuroscience-informed approach affords the opportunity to unpack potential neurobiological mechanisms that may underscore challenges in maternal caregiving behavior among mothers with addictions and provide new directions for parenting interventions.

Findings

Consistent with theoretical models of parenting and addictions, five studies evidence both hypo- and hyper-reactivity to infant affective cues across neuroimaging methods and tasks that incorporate both infant face and cry stimuli. Three structural and resting-state brain studies as a function of maternal substance use are also reported.

Conclusions

While human neuroimaging research converges in showing that maternal substance use is associated with differential reactivity to infant affective cues, further multi-level/multi-modal, longitudinal, and dimensional research is critically needed to advance this area of investigation.

Oxytocin receptors in the midbrain dorsal raphe are essential for postpartum maternal social and affective behaviors

Oxytocin receptors (OTRs) in the midbrain dorsal raphe (DR; the source of most forebrain serotonin) have recently been identified as a potential pharmacological target for treating numerous psychiatric disorders. However, almost all research on this topic has been conducted on males and the role of DR OTRs in female social and affective behaviors is mostly unknown. This may be particularly relevant during early motherhood, which is a time of high endogenous oxytocin signaling, but also a time of elevated risk for psychiatric dysfunction. To investigate whether OTRs in the DR are necessary for postpartum female social and affective behaviors, we constructed and then injected into the DR an adeno-associated virus permanently expressing an shRNA targeting OTR mRNA. We then observed a suite of social and affective behaviors postpartum. OTR knockdown in the maternal DR led to pup loss after parturition, decreased nursing, increased aggression, and increased behavioral despair. These effects of OTR knockdown in the DR may be due to disrupted neuroplasticity in the primary somatosensory cortex (S1), which mediates maternal sensitivity to the tactile cues from young, as we found significantly more plasticity-restricting perineuronal nets (PNNs) in the S1 rostral barrel field and fewer PNNs in the caudal barrel field of OTR-knockdown mothers. These results demonstrate that OTRs in the midbrain DR are essential for postpartum maternal social and affective behaviors, are involved in postpartum cortical plasticity, and suggest that pharmacotherapies targeting OTRs in the DR could be effective treatments for some peripartum affective disorders.

Developmental gains and losses during parenthood

The onset of parenthood irrevocably changes the landscape of adults' functioning, amplifying the potential for parents' experiences of both developmental losses and gains/growth, in context of increased responsibilities and more limited access to environmental resources/supports. In this article, we draw on dual theoretical lenses to integrate the frameworks of Baltes' lifespan development theory of gains and loss and Bronfenbrenner's bioecological model. We summarize empirical evidence in relation to a normative transition, exemplified by the transition to parenthood, and a non-normative event, the Coronavirus (COVID-19) pandemic, and show that parents' experiences of developmental loss and gains/growth are inextricably linked. Our findings illustrate how parents' losses/gains are influenced by a broad range of individual and environmental factors, with implications for parent prevention/intervention programs.