Pregnancy, postpartum and parity: Resilience and vulnerability in brain health and disease

Inflammatory signalling during the perinatal period: Implications for short- and long-term disease risk

During pregnancy and the postpartum, there are dynamic fluctuations in steroid and peptide hormone levels as well as inflammatory signalling. These changes are required for a healthy pregnancy and can persist well beyond the postpartum. Many of the same hormone and inflammatory signalling changes observed during the perinatal period also play a role in symptoms related to autoimmune disorders, psychiatric disorders, and perhaps neurodegenerative disease later in life. In this review, we outline hormonal and immunological shifts linked to pregnancy and the postpartum and discuss the possible role of these shifts in increasing psychiatric, neurodegenerative disease risk and autoimmune symptoms during and following pregnancy. Furthermore, we discuss how key variables such as the number of births (parity) and sex of the fetus can influence inflammatory signalling, and possibly future disease risk, but are not often studied. We conclude by discussing the importance of studying female experiences such as pregnancy and parenting on physiology and disease.

Beyond Birth Control: The Neuroscience of Hormonal Contraceptives

Hormonal contraceptives (HCs) are one of the most highly prescribed classes of drugs in the world used for both contraceptive and noncontraceptive purposes. Despite their prevalent use, the impact of HCs on the brain remains inadequately explored. This review synthesizes recent findings on the neuroscience of HCs, with a focus on human structural neuroimaging as well as translational, nonhuman animal studies investigating the cellular, molecular, and behavioral effects of HCs. Additionally, we consider data linking HCs to mood disorders and dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and stress response as a potential mediator. The review also addresses the unique sensitivity of the adolescent brain to HCs, noting significant changes in brain structure and function when HCs are used during this developmental period. Finally, we discuss potential effects of HCs in combination with smoking-derived nicotine on outcomes of ischemic brain damage. Methodological challenges, such as the variability in HC formulations and user-specific factors, are acknowledged, emphasizing the need for precise and individualized research approaches. Overall, this review underscores the necessity for continued interdisciplinary research to elucidate the neurobiological mechanisms of HCs, aiming to optimize their use and improve women's health.

Hormonal contraceptives and behavior: Updating the potent state of the nascent science

Hundreds of millions of people worldwide use hormonal contraceptives (HCs), which have been an essential part of women's reproductive health care for decades. Throughout that time, however, research on the neural and behavioral consequences of HCs was minimal and plagued by poor methodology. HC effects - and users - were assumed to be homogenous. Fortunately, there has been a recent upswell in the number and quality of investigations, affording tentative conclusions about the roles of HCs in spatial cognition and mental health, particularly depression. Thus, this paper leverages findings from the past few years to highlight the heterogeneous aspects of use that seem to matter for behavior - ranging from variation in hormonal contraceptive formulations and routes of administration to individual differences among users linked to age and reproductive health history. This paper closes with five tips for future research that will help capture and clarify heterogeneity in potential relations between HCs and behavior, namely data collection, regional access, lifespan factors, gender, and collaboration. HCs are sociopolitically provocative and research on their potential behavioral neuroendocrine impacts is becoming increasingly popular. It is, therefore, imperative for scientists to conduct replicable and robust empirical investigations, and to communicate findings with the nuance that the heterogeneity among users and effects requires.

Effects of a Person's Lactation History on Later-Life Development of Alzheimer's Disease: An Integrative Review

Objective: The purpose of this integrative review is to assess the existing evidence regarding the effects of a person's lactation history on later-life development of Alzheimer's disease. Methods: The authors searched the electronic databases PubMed, Cumulative Index to Nursing and Allied Health Literature, Scopus, and Excerpta Medica dataBASE, and performed backward reference searches using search terms such as, "Alzheimer's disease, dementia," and "breastfeeding, lactation." Authors selected relevant records through the application of inclusion and exclusion criteria and reading the titles, abstracts, or records in full. Results: In total, 400 articles were identified, and 10 articles meeting inclusion criteria were analyzed. Authors extracted data following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and scored levels of evidence according to Melnyk and Fineout-Overholt. Data were organized according to themes of breastfeeding duration, ever having breastfed, and indirect effects of breastfeeding. Conclusions: Breastfeeding may have neuroprotective effects for the lactating person and reduce the risk of later-life development of Alzheimer's disease. However, future research is necessary to determine the generalizability of this association.

Adolescent stress accelerates postpartum novelty recognition impairment in 5xFAD mice

Pregnancy and the postpartum period induce physiological changes that can influence women's cognitive functions. Alzheimer's disease (AD) has a higher prevalence in women and is exacerbated by early life stress. In the present study, we found that late adolescent social isolation combined with the experience of pregnancy and delivery accelerates the onset of cognitive deficits in 5xFAD dams, particularly affecting their ability to recognize novelty. These cognitive deficits manifested as early as 16 weeks, earlier than the usual timeline for these mice, and were closely associated with increased levels of corticosterone, suggesting dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Notably, the presence of β-amyloid plaques in brain regions associated with novelty recognition did not significantly contribute to these deficits. This highlights the potential role of stress and HPA axis dysregulation in the development of cognitive impairments related to AD, and underscores the need for further investigation.

Late-onset multiple sclerosis: disability trajectories in relapsing-remitting patients of the Italian MS Registry

BACKGROUND

Generally infrequent, multiple sclerosis (MS) with late onset (LOMS) is characterized by an onset over the age of 50 and a mainly progressive course, while relapsing-remitting (RR) forms are less frequently observed and explored. This study aimed to characterize a large cohort of MS patients with RRMS at onset to assess the baseline factors related to the worst disability trajectories and explore the role of LOMS.

METHODS

The data were extracted from the Italian MS Register (IMSR). Disability trajectories, defined using at least two and up to twenty expanded disability status scale (EDSS) assessments annually performed, were implemented using group-based trajectory models (GBTMs) to identify different groups with the same trajectories over time. MS profiles were explored using multinomial logistic regression.

RESULTS

A total of 16,159 RR patients [1012 (6.26%) presented with LOMS] were analyzed. The GBTM identified four disability trajectories. The group with the most severe EDSS trend included 12.3% of the patients with a mean EDSS score > 4, which increased over time and exceeded 6 score. The group with medium severity EDSS trend comprised 21.9% of the patients and showed a change in EDSS > 3 scores over time. The largest group with 50.8% of patients reported a constant EDSS of 2 score. Finally, the benign group comprised 14.9% of the patients with a low and constant EDSS of 1 score over time. The probability of being in the worst groups increased if the patient was male; had LOMS or experienced brainstem, spinal, or supratentorial symptoms.

CONCLUSIONS

Four MS severity profiles among RRMS patients in the IMSR have been reported, with LOMS being associated with a rapid worsening of EDSS scores. These findings have important implications for recognizing and managing how older age, aging, and age-related factors interact with MS and its evolution.

Association Between Pandemic-Related Maternal Perinatal Anxiety and Early Postpartum Breastfeeding Success

BACKGROUND AND OBJECTIVES

Prior studies have shown conflicting results on the impact of maternal anxiety on breastfeeding initiation and success. Furthermore, a substantial increase in maternal anxiety levels was shown in response to the COVID-19 pandemic. In this study, we aimed to investigate the relationship between maternal perinatal anxiety induced by the COVID-19 pandemic and early breastfeeding outcomes.

MATERIALS AND METHODS

This cross-sectional study was conducted in two regional maternity hospitals, involving 220 first-time pregnant patients with a gestational age of ≥37 weeks. All patients had no current diagnosis of COVID-19 and no cases of COVID-19 in their close environment at the time of admission. At 24-48 hours postpartum or at the time of discharge, three following scoring systems were employed: the Coronavirus Anxiety Scale (CAS), the State-Trait Anxiety Inventory (STAI), and the LATCH (short for latch, audible swallowing, type of nipple, comfort, and hold) score. A LATCH score of ≥8 was chosen as the cutoff point for defining successful breastfeeding performance. Spearman's rank correlation was used to evaluate relationships between the CAS, STAI scores, maternal and infant factors, and LATCH scores.

RESULTS

There were no differences in baseline characteristics between groups categorized as successful and unsuccessful in breastfeeding initiation. The mean total STAI score was 86.3±13.2, the CAS score was 1.07±1.91, and the LATCH score was 8.42±1.7. Although there was an increase in State-Trait Anxiety Inventory-State Anxiety (STAI-S) scores compared to State-Trait Anxiety Inventory-Trait Anxiety (STAI-T) scores, and the STAI-S score and CAS score were higher in the unsuccessful group, these differences did not reach statistical significance (p = 0.22 and 0.16, respectively). When we evaluated the correlation of the LATCH score with STAI total, STAI-S and STAI-T scores, CAS score, and maternal and infant factors, only the type of delivery showed a significant correlation with the LATCH score (p = 0.008).

CONCLUSIONS

Early postpartum breastfeeding efficiency, as measured by the LATCH score, was only correlated with the type of delivery. No significant correlation was found between pandemic-related maternal perinatal anxiety and early postpartum breastfeeding success.

Connections between reproductive health and cognitive aging among women enrolled in the HCHS/SOL and SOL-INCA

INTRODUCTION

Reproductive health history may contribute to cognitive aging and risk for Alzheimer's disease, but this is understudied among Hispanic/Latina women.

METHODS

Participants included 2126 Hispanic/Latina postmenopausal women (44 to 75 years) from the Study of Latinos-Investigation of Neurocognitive Aging. Survey linear regressions separately modeled the associations between reproductive health measures (age at menarche, history of oral contraceptive use, number of pregnancies, number of live births, age at menopause, female hormone use at Visit 1, and reproductive span) with cognitive outcomes at Visit 2 (performance, 7-year change, and mild cognitive impairment [MCI] prevalence).

RESULTS

Younger age at menarche, oral contraceptive use, lower pregnancies, lower live births, and older age at menopause were associated with better cognitive performance. Older age at menarche was protective against cognitive change. Hormone use was linked to lower MCI prevalence.

DISCUSSION

Several aspects of reproductive health appear to impact cognitive aging among Hispanic/Latina women.

Associations of reproductive factors and exogenous estrogens with global and domain-specific cognition in later life

INTRODUCTION

Few studies have comprehensively examined the impact of reproductive factors (i.e., reproductive window, parity, hormonal contraception [HC], and menopausal hormone therapy [MHT]) on global and domain-specific cognition in later life.

METHODS

We studied a population-based sample of 2458 women (median age 74.2 years) residing in Olmsted County, Minnesota; participants underwent a clinical evaluation and comprehensive cognitive testing.

RESULTS

The length of a woman's reproductive window was not associated with cognition. Higher parity was associated with greater cognitive decline in all domains. Ever HC use was associated with less decline in all domains. Ever MHT use was associated with greater decline in global cognition and all domain-specific z-scores except visuospatial; results were driven by women who initiated MHT 5 or more years after menopause. Additional adjustments for APOE and vascular-related covariates did not attenuate the results.

DISCUSSION

Multiple reproductive risk factors are associated with cognitive decline in later life.

HIGHLIGHTS

The length of a woman's reproductive window was not associated with cognition longitudinally. Greater parity was associated with greater cognitive decline longitudinally. Ever HC use was associated with less decline in global cognition and all domain-specific z-scores longitudinally (all p < 0.01). Ever MHT use was associated with greater decline in global cognition and all domain-specific z-scores except visuospatial longitudinally (all p < 0.01). The greatest cognitive decline was among women who initiated MHT more than 5 years after menopause.

Previous pregnancies might mitigate cortical brain differences associated with surgical menopause

Surgical menopause causes a sharp drop in estrogen levels in middle-aged women, thus preventing the gradual physiological adaptation that is characteristic of the perimenopause. Previous studies suggest that surgical menopause might increase the risk of dementia later in life. In addition, the transition to motherhood entails long-lasting endocrine and neuronal adaptations. We compared differences in whole-brain cortical volume between women who reached menopause by surgery and a group of women who reached spontaneous non-surgical menopause and determined whether these cortical differences were influenced by previous childbearing. Using surface-based neuroimaging techniques, we investigated cortical volume differences in 201 middle-aged women (134 women who experienced non-surgical menopause, 78 of whom were parous women; and 67 women who experienced surgical menopause, 39 of whom were parous women). We found significant atrophy in the frontal and temporal regions in women who experienced surgical menopause. Nulliparous women with surgical menopause showed significant lower cortical volume in the left temporal gyrus extending to the medial temporal lobe cortex, as well as in the precuneus bilaterally compared to parous women with surgical menopause; whereas our results revealed no significant differences between parous women with surgical menopause and both parous and nulliparous women who reached a non-surgical menopause. Furthermore, in the surgical menopause group, we found a negative correlation between cortical volume and age at first pregnancy in the temporal lobe. Our study suggests that the long-term brain remodeling of parity may mitigate the neural impact of the sudden drop in estrogen levels that characterizes surgical menopause.

Mitochondrial might: powering the peripartum for risk and resilience

The peripartum period, characterized by dynamic hormonal shifts and physiological adaptations, has been recognized as a potentially vulnerable period for the development of mood disorders such as postpartum depression (PPD). Stress is a well-established risk factor for developing PPD and is known to modulate mitochondrial function. While primarily known for their role in energy production, mitochondria also influence processes such as stress regulation, steroid hormone synthesis, glucocorticoid response, GABA metabolism, and immune modulation - all of which are crucial for healthy pregnancy and relevant to PPD pathology. While mitochondrial function has been implicated in other psychiatric illnesses, its role in peripartum stress and mental health remains largely unexplored, especially in relation to the brain. In this review, we first provide an overview of mitochondrial involvement in processes implicated in peripartum mood disorders, underscoring their potential role in mediating pathology. We then discuss clinical and preclinical studies of mitochondria in the context of peripartum stress and mental health, emphasizing the need for better understanding of this relationship. Finally, we propose mitochondria as biological mediators of resilience to peripartum mood disorders.

Role of caveolin-1 in metabolic programming of fetal brain

Mice lacking caveolin-1 (Cav1), a key protein of plasma membrane, exhibit brain aging at an early adult stage. Here, integrative analyses of metabolomics, transcriptomics, epigenetics, and single-cell data were performed to test the hypothesis that metabolic deregulation of fetal brain due to the ablation of Cav1 is linked to brain aging in these mice. The results of this study show that lack of Cav1 caused deregulation in the lipid and amino acid metabolism in the fetal brain, and genes associated with these deregulated metabolites were significantly altered in the brain upon aging. Moreover, ablation of Cav1 deregulated several metabolic genes in specific cell types of the fetal brain and impacted DNA methylation of those genes in coordination with mouse epigenetic clock. The findings of this study suggest that the aging program of brain is confounded by metabolic abnormalities in the fetal stage due to the absence of Cav1.

Biomarkers of Postpartum Depression: A Narrative Review

Postpartum depression (PPD) is a disorder that impairs the formation of the relationship between mother and child, and reduces the quality of life for affected women to a functionally significant degree. Studying markers associated with PPD can help in early detection, prevention, or monitoring treatment. The purpose of this paper is to review biomarkers linked to PPD and to present selected theories on the pathogenesis of the disease based on data from biomarker studies. The complex etiology of the disorder reduces the specificity and sensitivity of markers, but they remain a valuable source of information to help clinicians. The biggest challenge of the future will be to translate high-tech methods for detecting markers associated with postpartum depression into more readily available and less costly ones. Population-based studies are needed to test the utility of potential PPD markers.

Potential Protective Role of Pregnancy and Breastfeeding in Delaying Onset Symptoms Related to Multiple Sclerosis

The impact of pregnancy and breastfeeding on the development and outcomes of Multiple sclerosis (MS) has been debated for decades. Since several factors can influence the evolution of the disease, the protective role of multiparity and breastfeeding remains uncertain, as well the role of hormone replacement therapy in the perimenopausal period. We report two cases of relatively late-onset MS in two parous women, who developed their first neurological symptoms after six and nine pregnancies, respectively. Both women breastfed each of their children for 3 to 12 months. One of them underwent surgical menopause and received hormone replacement therapy for 7 years before MS onset. We performed a systematic literature review to highlight the characteristics shared by women who develop the disease in similar conditions, after unique hormonal imbalances, and to collect promising evidence on this controversial issue. Several studies suggest that the beneficial effects of pregnancy and breastfeeding on MS onset and disability accumulation may only be realized when several pregnancies occur. However, these data on pregnancy and breastfeeding and their long-term benefits on MS outcomes suffer from the possibility of reverse causality, as women with milder impairment might choose to become pregnant more readily than those with a higher level of disability. Thus, the hypothesis that multiparity might have a protective role on MS outcomes needs to be tested in larger prospective cohort studies of neo-diagnosed women, evaluating both clinical and radiological features at presentation.

Steady electrocorticogram characteristics predict specific stress-induced behavioral phenotypes

Introduction

Depending on the individual, exposure to an intense stressor may, or may not, lead to a stress-induced pathology. Predicting the physiopathological evolution in an individual is therefore an important challenge, at least for prevention. In this context, we developed an ethological model of simulated predator exposure in rats: we call this the multisensorial stress model (MSS). We hypothesized that: (i) MSS exposure can induce stress-induced phenotypes, and (ii) an electrocorticogram (ECoG) recorded before stress exposure can predict phenotypes observed after stress.

Methods

Forty-five Sprague Dawley rats were equipped with ECoG telemetry and divided into two groups. The Stress group (n = 23) was exposed to an MSS that combined synthetic fox feces odor deposited on filter paper, synthetic blood odor, and 22 kHz rodent distress calls; the Sham group (n = 22) was not exposed to any sensorial stimulus. Fifteen days after initial exposure, the two groups were re-exposed to a context that included a filter paper soaked with water as a traumatic object (TO) reminder. During this re-exposure, freezing behavior and avoidance of the filter paper were measured.

Results

Three behaviors were observed in the Stress group: 39% developed a fear memory phenotype (freezing, avoidance, and hyperreactivity); 26% developed avoidance and anhedonia; and 35% made a full recovery. We also identified pre-stress ECoG biomarkers that accurately predicted cluster membership. Decreased chronic 24 h frontal Low θ relative power was associated with resilience; increased frontal Low θ relative power was associated with fear memory; and decreased parietal β2 frequency was associated with the avoidant-anhedonic phenotype.

Discussion

These predictive biomarkers open the way to preventive medicine for stress-induced diseases.

A subpopulation of oxytocin neurons initiate expression of CRF receptor 1 (CRFR1) in females post parturition

Oxytocin (OT) is essential for successful reproduction, particularly during parturition and lactation. During the postpartum period, OT also influences maternal behavior to promote bonding between mothers and their newborns, and increases stress resilience. However, the mechanism by which stress influences OT neuron activity and OT release has remained unclear. Here, we provide evidence that a subpopulation of OT neurons initiate expression of the receptor for the stress neuropeptide Corticotropin Releasing Factor (CRF), CRFR1, in reproductive females. OT neuron expression of CRFR1 begins at the first parturition and increases during the postpartum period until weaning. The percentage of OT neurons that express CRFR1 increases with successive breeding cycles until it reaches a plateau of 20-25% of OT neurons. OT neuron expression of CRFR1 in reproductive females is maintained after they are no longer actively breeding. CRFR1 expression leads to activation of OT neurons when animals are stressed. We propose a model in which direct CRF signaling to OT neurons selectively in reproductive females potentiates OT release to promote stress resilience in mothers.

Ovarian steroid hormones: A long overlooked but critical contributor to brain aging and Alzheimer's disease

Ovarian hormones, particularly 17β-estradiol, are involved in numerous neurophysiological and neurochemical processes, including those subserving cognitive function. Estradiol plays a key role in the neurobiology of aging, in part due to extensive interconnectivity of the neural and endocrine system. This aspect of aging is fundamental for women's brains as all women experience a drop in circulating estradiol levels in midlife, after menopause. Given the importance of estradiol for brain function, it is not surprising that up to 80% of peri-menopausal and post-menopausal women report neurological symptoms including changes in thermoregulation (vasomotor symptoms), mood, sleep, and cognitive performance. Preclinical evidence for neuroprotective effects of 17β-estradiol also indicate associations between menopause, cognitive aging, and Alzheimer's disease (AD), the most common cause of dementia affecting nearly twice more women than men. Brain imaging studies demonstrated that middle-aged women exhibit increased indicators of AD endophenotype as compared to men of the same age, with onset in perimenopause. Herein, we take a translational approach to illustrate the contribution of ovarian hormones in maintaining cognition in women, with evidence implicating menopause-related declines in 17β-estradiol in cognitive aging and AD risk. We will review research focused on the role of endogenous and exogenous estrogen exposure as a key underlying mechanism to neuropathological aging in women, with a focus on whether brain structure, function and neurochemistry respond to hormone treatment. While still in development, this research area offers a new sex-based perspective on brain aging and risk of AD, while also highlighting an urgent need for better integration between neurology, psychiatry, and women's health practices.

GABA System Modifications During Periods of Hormonal Flux Across the Female Lifespan

The female lifespan is marked by periods of dramatic hormonal fluctuation. Changes in the ovarian hormones estradiol and progesterone, in addition to the progesterone metabolite allopregnanolone, are among the most significant and have been shown to have widespread effects on the brain. This review summarizes current understanding of alterations that occur within the GABA system during the major hormonal transition periods of puberty, the ovarian cycle, pregnancy and the postpartum period, as well as reproductive aging. The functional impacts of altered inhibitory activity during these times are also discussed. Lastly, avenues for future research are identified, which, if pursued, can broaden understanding of the GABA system in the female brain and potentially lead to better treatments for women experiencing changes in brain function at each of these hormonal transition periods.

Effects of post-ovariectomy time frame and age on the antidepressant-like actions of estradiol and prolame in female rats

Estrogen replacement therapy (ERT) is an effective treatment for symptoms associated with climacteric and depression some women experience during perimenopause and menopause. The antidepressant-like effects of ERT may depend on the type of estrogen, age, and time when restitution is initiated after hormonal decline. Prolame is a synthetic steroid with estrogenic and antidepressant-like effects that may produce fewer adverse effects. We hypothesize that such actions of prolame on females depend on age and the duration of hormone deprivation period. We assessed the antidepressant-like effects of 17β-estradiol (E₂) and prolame in young and middle-aged rats across different post-ovariectomy (Ovx) time frames. Independent groups of young adults and middle-aged female rats were tested in the forced swimming test (FST) at 3, 8, 16, and 24 weeks post-Ovx. Prolame and E₂ were administered in a sub-chronic schedule consisting of three injections before the FST. Likewise, the utero-trophic effects of these hormones were analyzed. We found that E₂ and prolame reduced immobility in young rats 3 and 8 weeks after Ovx; in contrast, only prolame produced this effect in middle-aged rats three weeks post-Ovx. E₂ and prolame increased the animals' utero-somatic index at all post-Ovx times, but the action of E₂ and prolame produced a greater response in young adult rats. Our findings showed that the antidepressant-like effects of E₂ and prolame depend on the post-Ovx time frame, age, and estrogen type. Interestingly, our results indicate that, in contrast to E₂, prolame maintained its antidepressant effect in middle-aged rats.

The peripartum period involvement in the development of post-partum depression. A prospective cohort study

PURPOSE

This study explores postpartum depression (PPD) in women who screened negative in mid-pregnancy to assess the impact of the peripartum period on the development of depressive symptoms.

METHODS

A prospective cohort study was carried out in two facilities in Argentina. The Edinburgh postnatal depression scale (EPDS) scale was applied to pregnant women between weeks 20-24 gestation, and those screening negative (<10) were included in the cohort. Participants were followed up until the 4th week postpartum, when the EPDS was repeated. If positive, a semi-structured clinical interview was applied (MINI) to define the diagnosis.

RESULTS

A total of 112 pregnant women were eligible for the follow-up. At the 4th week postpartum, 14 women (12.5%, CI 95% 7.0; 20.1) screened positive using a cutoff point of 10 or more in the EPDS. Of those screened positive in the EPDS, two participants (1.8%, CI 95% 0.2-6.3) had a Major Depressive Disorder. Newborn admission to the Intensive Care Unit, hospitalization of the newborn after discharge, abuse during childbirth, and lack of company during labor were identified as peripartum risk factors.

CONCLUSIONS

This study reinforces the relevance of women and newborn mental health care during the hospitalization process surrounding peripartum. The women and newborn hospitalization process should be better explored to understand the contribution to PPD and design and test strategies to alleviate the impact of maternal depression.

Endogenous and Exogenous Estrogen Exposures: How Women's Reproductive Health Can Drive Brain Aging and Inform Alzheimer's Prevention

After advanced age, female sex is the major risk factor for late-onset Alzheimer's disease (AD), the most common cause of dementia affecting over 24 million people worldwide. The prevalence of AD is higher in women than in men, with postmenopausal women accounting for over 60% of all those affected. While most research has focused on gender-combined risk, emerging data indicate sex and gender differences in AD pathophysiology, onset, and progression, which may help account for the higher prevalence in women. Notably, AD-related brain changes develop during a 10-20 year prodromal phase originating in midlife, thus proximate with the hormonal transitions of endocrine aging characteristic of the menopause transition in women. Preclinical evidence for neuroprotective effects of gonadal sex steroid hormones, especially 17β-estradiol, strongly argue for associations between female fertility, reproductive history, and AD risk. The level of gonadal hormones to which the female brain is exposed changes considerably across the lifespan, with relevance to AD risk. However, the neurobiological consequences of hormonal fluctuations, as well as that of hormone therapies, are yet to be fully understood. Epidemiological studies have yielded contrasting results of protective, deleterious and null effects of estrogen exposure on dementia risk. In contrast, brain imaging studies provide encouraging evidence for positive associations between greater cumulative lifetime estrogen exposure and lower AD risk in women, whereas estrogen deprivation is associated with negative consequences on brain structure, function, and biochemistry. Herein, we review the existing literature and evaluate the strength of observed associations between female-specific reproductive health factors and AD risk in women, with a focus on the role of endogenous and exogenous estrogen exposures as a key underlying mechanism. Chief among these variables are reproductive lifespan, menopause status, type of menopause (spontaneous vs. induced), number of pregnancies, and exposure to hormonal therapy, including hormonal contraceptives, hormonal therapy for menopause, and anti-estrogen treatment. As aging is the greatest risk factor for AD followed by female sex, understanding sex-specific biological pathways through which reproductive history modulates brain aging is crucial to inform preventative and therapeutic strategies for AD.

The validity of the residuals approach to measuring resilience to adverse childhood experiences

BACKGROUND

Resilience is broadly defined as the ability to maintain or regain functioning in the face of adversity. Recent work to harmonise the quantification and definition of resilience quantifies resilience as the residual variance in psychosocial functioning that remains after accounting for adversity exposure. However, there have been no published studies that have formally investigated the validity of this approach. Considering this, we examine the construct and predictive validity of the residuals approach using participants from the Avon Longitudinal Study of Parents and Children (ALSPAC), a multigenerational, longitudinal cohort study.

METHODS

We regressed exposures of adolescent adversity on adolescent psychopathology scores using the Strength and Difficulties Questionnaire and obtained the residual variance. We investigated construct validity by analysing whether previously identified demographic and resilience factors significantly predicted resilience. Predictive validity of resilience was investigated by comparing the predictive power of resilience with other determinants of psychosocial functioning on two developmental outcomes: depressive symptoms at 18 years, measured by the Short Moods and Feelings Questionnaire, and NEET (Not in Employment, Education or Training) status at 17 and 23 years. The associations between depressive symptoms at 18, resilience, ACEs and covariates were tested using multiple linear regression. NEET status at 17 and 23 were run as separate binary multiple logistic regression models to test associations with resilience and known demographics previously associated with NEET status.

RESULTS

Seven previously identified protective factors, including self-esteem, positive sibling relationship, temperament, and positive perception of school, significantly predicted resilience to adolescent psychopathology, thus providing strong construct validity. Resilience significantly predicted a reduction in depressive symptoms at 18 years, and significantly decreased the likelihood of having NEET status at both 17 years and 23 years, even after taking into account early childhood adversity and other risk factors. None of the socioeconomic factors were significantly associated with resilience.

CONCLUSIONS

Our study demonstrates that the residuals method of operationalising resilience has good construct and predictive validity yet recommend replication studies. It has the potential to advance research into the mechanisms and modifiability of resilience.

TRIAL REGISTRATION

Not applicable.

Immune System Alterations and Postpartum Mental Illness: Evidence From Basic and Clinical Research

The postpartum period is a time associated with high rates of depression and anxiety as well as greater risk for psychosis in some women. A growing number of studies point to aberrations in immune system function as contributing to postpartum mental illness. Here we review evidence from both clinical and animal models suggesting an immune component to postpartum depression, postpartum anxiety, and postpartum psychosis. Thus far, clinical data primarily highlights changes in peripheral cytokine signaling in disease etiology, while animal models have begun to provide insight into the immune environment of the maternal brain and how central inflammation may also be contributing to postpartum mental illnesses. Further research investigating peripheral and central immune function, along with neural and endocrine interactions, will be important in successfully developing novel prevention and treatment strategies for these serious disorders that impact a large portion of new mothers.

Stress-Related Mental Health Disorders and Inflammation in Pregnancy: The Current Landscape and the Need for Further Investigation

Many studies have focused on psychoimmunological mechanisms of risk for stress-related mental health disorders. However, significantly fewer studies have focused on understanding mechanisms of risk for stress-related disorders during pregnancy, a period characterized by dramatic changes in both the innate and adaptive immune systems. The current review summarizes and synthesizes the extant literature on the immune system during pregnancy, as well as the sparse existing evidence highlighting the associations between inflammation and mood, anxiety, and fear-related disorders in pregnancy. In general, pregnant persons demonstrate lower baseline levels of systemic inflammation, but respond strongly when presented with an immune challenge. Stress and trauma exposure may therefore result in strong inflammatory responses in pregnant persons that increases risk for adverse behavioral health outcomes. Overall, the existing literature suggests that stress, trauma exposure, and stress-related psychopathology are associated with higher levels of systemic inflammation in pregnant persons, but highlight the need for further investigation as the existing data are equivocal and vary based on which specific immune markers are impacted. Better understanding of the psychoimmunology of pregnancy is necessary to reduce burden of prenatal mental illness, increase the likelihood of a successful pregnancy, and reduce the intergenerational impacts of prenatal stress-related mental health disorders.

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.

Stratification by Sex and Hormone Level When Contrasting Men and Women in Schizophrenia Trials Will Improve Personalized Treatment

BACKGROUND

Sex and gender differences have been reported in the prevalence, expression, treatment response, and outcome of schizophrenia, but most reports are based on relatively small samples that have not been stratified for the impact of sex hormone levels. This literature review aims to show how women's hormone levels can impact the results of male/female comparisons.

METHODS

This is a narrative review of data from publications of the last decade.

RESULTS

Epidemiologic evidence, reports of the impact of hormones on cognition, results of sexually dimorphic responses to treatment, and male/female trajectories of illness over time all suggest that female hormone fluctuations exert major effects on male/female differences in schizophrenia.

CONCLUSIONS

Information on hormonal status in women participants is rarely available in clinical studies in schizophrenia, which makes male/female comparisons largely uninterpretable. These are the current challenges. Opportunities for individualized treatment are growing, however, and will undoubtedly result in improved outcomes for both women and men in the future.

Resilience and Stress during Pregnancy: A Comprehensive Multidimensional Approach in Maternal and Perinatal Health

This narrative review addresses resilience and stress during pregnancy, which is part of a broader concept of maternal health. Pregnancy and postpartum are opportune periods for health promotion interventions, especially because the close contact of the women with health professionals. In this way, it can be considered a useful window of opportunity to identify women at higher risk for adverse outcomes. Integrated health is a concept that aims at providing comprehensive care related to the promotion of individuals' physical, mental, and social well-being. In this context, stress during pregnancy has been targeted as a remarkable condition to be addressed whether due to individual issues, social issues, or specific pregnancy issues, since it is directly and indirectly associated with pregnancy complications. Stress is associated with preterm birth, postpartum depression, anxiety, child neurodevelopment, and fetal distress. The way that an individual faces a stressful and adverse situation is called resilience; this reaction is individual, dynamic, and contextual, and it can affect maternal and fetal outcomes. Low resilience has been associated with poorer pregnancy outcomes. The social context of pregnancy can act as a protective or contributory (risk) factor, indicating that environments of high social vulnerability play a negative role in resilience and, consequently, in perceived stress. A given stressor can be enhanced or mitigated depending on the social context that was imposed, as well as it can be interpreted as different degrees of perceived stress and faced with a higher or lower degree of resilience. Understanding these complex mechanisms may be valuable for tackling this matter. Therefore, in the pregnancy-puerperal period, the analysis of the stress-resilience relationship is essential, especially in contexts of greater social vulnerability, and is a health-promoting factor for both the mother and baby.

Prolactin as a neuroendocrine clue in sexual function of women across the reproductive life cycle: an expert point of view

Prolactin is a proteic hormone best known for its role in enabling the production of milk by female mammals. Secreted by the pituitary gland in response to the stimuli of eating, estrogen treatment, mating, ovulation and nursing, prolactin is involved in over 300 separate processes in a range of vertebrates, including humans. The hormone is released in a pulsatile manner and plays an essential role in metabolism, as well as in the regulation of the immune system and pancreatic development. Nevertheless, prolactin exerts other relevant roles, as it acts at the central nervous system level to modulate behavior, arousal and sexuality. In this experts' opinion, we aim to give insights into the main activities of prolactin to advance the ability of medical doctors and specialists in obstetrics and gynecology to provide more emphasis in their clinical practices to the link between prolactin and sexuality.

Breastfeeding during COVID-19: A Narrative Review of the Psychological Impact on Mothers

The COVID-19 pandemic has altered the normal course of life, with measures to reduce the virus spread impacting motherhood expectations and, in particular, breastfeeding practices. This study aimed to review evidence regarding the impact of COVID-19 on breastfeeding plans and how these relate to women's psychological outcomes. Searches were conducted on PubMed and Web of Science for studies in English, Spanish, and Portuguese between January 2020 and January 2021. All study designs and pre-prints were considered. Twelve studies were included. Reports suggest that COVID-19 impacts differently on breastfeeding plans, which in turn leads to distinctive mental health outcomes. Positive breastfeeding experiences have been observed when mothers perceive that they have more time for motherhood, which may be associated with better mental health outcomes. Negative breastfeeding experiences have been observed when mothers are separated from their newborns, when mothers struggle with breastfeeding, or when mothers perceive decreased family and professional support, which seems to be associated with worse mental health outcomes. These preliminary results highlight the need for further research into the association between COVID-19, breastfeeding expectations, and maternal mental health. Filling this gap will foster the development of guidelines and interventions to better support mothers experiencing the obstacles of COVID-19 pandemic.

Animal models built for women's brain health: Progress and potential

Women and men have different levels of risk for a variety of brain disorders. Despite this well-known epidemiological finding, preclinical work utilizing animal models has historically only included male animals. The policies of funders to require consideration of sex as a biological variable has shifted the momentum to include female animals in preclinical neuroscience and to report findings by sex. However, there are many biological questions related to brain health that go beyond sex differences and are indeed specific to women. Here, the focus is on why animal models should be utilized in the pursuit of understanding women's brain health, a brief overview of what they have provided thus far, and why they still hold tremendous promise. This review concludes with a set of suggestions for how to begin to pursue translational animal models in a way that facilitates rapid success and harnesses the most powerful aspects of animal models.

Parity Attenuates Intraepithelial Corneal Sensory Nerve Loss in Female Mice

Aging impacts the ocular surface and reduces intraepithelial corneal nerve (ICN) density in male and female mice. Many researchers use retired breeders to study naturally aged female mice. Yet, the impact of parity and the length of time since breeders were retired on age-related changes in the intraepithelial corneal nerves is not known. Here we study 2 month (M) nulliparous (NP) females as well as 9M, 10M, and 11M NP and multiparous (MP) female mice to determine whether parity impacts the age-related decline seen in corneal axon density; 9M male mice are also included in these assessments. After showing that parity attenuates age-related loss in axon density, we also assess the impact of parity on corneal epithelial cell proliferation and find that it impacts cell proliferation and axon density normalized by cell proliferation. Stromal nerve arborization is also impacted by aging with parity enhancing stromal nerves in older mice. qPCR was performed on 20 genes implicated in ICN density using corneal epithelial RNA isolated from 10M NP and MP mice and showed that NGF expression was significantly elevated in MP corneal epithelium. Corneal sensitivity was significantly higher in 9M MP mice compared to NP mice and increased sensitivity in MP mice was accompanied by increased nerve terminals in the apical and middle cell layers. Together, these data show that parity in mice attenuates several aspects of the age-related decline seen on the ocular surface by retaining sensory axons and corneal sensitivity as mice age.