Hormonal and experiential correlates of maternal responsiveness during pregnancy and the puerperium in human mothers

Pregnancy renders anatomical changes in hypothalamic substructures of the human brain that relate to aspects of maternal behavior

Animal studies have shown that pregnancy is associated with neural adaptations that promote maternal care. The hypothalamus represents a central structure of the mammalian maternal brain and hormonal priming of specific hypothalamic nuclei plays a key role in the induction and expression of maternal behavior. In humans, we have previously demonstrated that becoming a mother involves changes in grey matter anatomy, primarily in association areas of the cerebral cortex. In the current study, we investigated whether pregnancy renders anatomical changes in the hypothalamus. Using an advanced delineation technique, five hypothalamic substructures were defined in longitudinal MRI scans of 107 women extracted from two prospective pre-conception cohort studies, including 50 women who were scanned before and after pregnancy and 57 nulliparous control women scanned at a similar time interval. We showed that becoming a mother is associated with volume reductions in the anterior-superior, superior tuberal and posterior hypothalamus. In addition, these structural changes related to hormonal levels during pregnancy and specific aspects of self-reported maternal behavior in late pregnancy, including maternal-fetal attachment and nesting behavior. These findings show that pregnancy leads to changes in hypothalamic anatomy and suggest that these contribute to the development of maternal behavior in humans, supporting the conservation of key aspects of maternal brain circuitry and their role in maternal behavior across species.

Do Parental Hormone Levels Synchronize During the Prenatal and Postpartum Periods? A Systematic Review

Physiological synchrony is the phenomenon of linked physiological processes among two or more individuals. Evidence of linkage between dyads has been found among a broad range of physiological indices, including the endocrine systems. During the transition to parenthood, both men and women undergo hormonal changes that facilitate parenting behavior. The present review sought to address the question as to whether hormonal synchronization occurs among expecting or new parents. A systematic literature search yielded 13 eligible records. The evidence of cortisol synchrony during the prenatal period, with additional testosterone, prolactin, and progesterone covariations in the time leading up to childbirth, was found to be most significant. During the postpartum period, parental synchrony was reported for oxytocin, testosterone, and cortisol levels. The implications of these covariations were found to translate into adaptive parenting behaviors and the facilitation of romantic bond. Associations with infant development were also reported, suggesting far-reaching effects of hormonal synchrony outside the parental dyad. The results highlight the importance of physiological interrelatedness during this sensitive period, underscoring the need for further research in this field. In view of the limited data available in this research domain, we have put forward a framework for future studies, recommending the adoption of standardized research protocols and repeated collections of specimens.

Effect of nausea and vomiting during pregnancy on mother-to-infant bonding and the mediation effect of postpartum depression: the Japan Environment and Children's Study

BACKGROUND

Mother-to-infant bonding (MIB) is critical for the health and well-being of the mother and child. Furthermore, MIB has been shown to boost the social-emotional development of infants, while also giving mothers a sense of happiness in raising their children. Nausea and vomiting during pregnancy (NVP) is a normal complication of pregnancy, occurring in approximately 50-90% of pregnant women in the early stages of pregnancy. Despite widespread knowledge of MIB and postpartum depression, little research attention has been given to the effects of NVP on MIB. This study aimed to investigate the relationship between NVP and MIB and the mediating effects of postpartum depression.

METHODS

We analyzed the data of 88,424 infants and 87,658 mothers from the Japan Environment and Children's Study (JECS), which is a government-funded nationwide birth prospective cohort study. The Japanese version of the Mother-to-Infant Bonding Scale (MIBS-J) was used to assess MIB, and the Edinburgh Postpartum Depression Scale (EPDS) was utilized to assess postpartum depression. We divided participants into four groups according to a self-reported questionnaire assessing NVP (No NVP, Mild NVP, Moderate NVP, and Severe NVP). MIB disorder was defined as a MIBS-J score ≥ 5. Logistic analysis was performed to evaluate the effect of NVP on MIB disorder at one year after delivery. A mediation analysis was conducted to examine whether postpartum depression mediated the association between NVP and MIBS-J scores.

RESULTS

The logistic regression analysis results revealed reduced risks of MIB disorder among mothers with Moderate NVP (adjusted OR 0.93; 95% confidence interval, 0.86-0.99) and Severe NVP (adjusted OR 0.81; 95% confidence interval, 0.74-0.89), compared to those with No NVP. The mediation analysis revealed that NVP positively correlated with MIBS-J score in the indirect effect via postpartum depression, while NVP (Mild NVP, Moderate NVP, and Severe NVP) negatively correlated with MIBS-J score in the direct effect.

CONCLUSION

The risks of MIB disorder were reduced in the Moderate NVP and Severe NVP mothers, although NVP inhibited the development of MIB via postpartum depression. The development of effective interventions for postpartum depression is important to improve MIB among mothers with NVP.

The transition to motherhood: linking hormones, brain and behaviour

We are witnessing a stark increase in scientific interest in the neurobiological processes associated with pregnancy and maternity. Convergent evidence suggests that around the time of labour, first-time mothers experience a specific pattern of neuroanatomical changes that are associated with maternal behaviour. Here we provide an overview of the human neurobiological adaptations of motherhood, focusing on the interplay between pregnancy-related steroid and peptide hormones, and neuroplasticity in the brain. We discuss which brain plasticity mechanisms might underlie the structural changes detected by MRI, which hormonal systems are likely to contribute to such neuroanatomical changes and how these brain mechanisms may be linked to maternal behaviour. This Review offers an overarching framework that can serve as a roadmap for future investigations.

Relationship of Estradiol and Progesterone with Partnership and Parity Among Bangladeshi and British Women of European Origin

Recent studies in social endocrinology have explored the effects of social relationships on female reproductive steroid hormones-estradiol and progesterone-investigating whether they are suppressed in partnered and parous women. Results have been mixed for these hormones although evidence is more consistent that partnered women and women with young children have lower levels of testosterone. These studies were sequential to earlier research on men, based on Wingfield's Challenge Hypothesis, which showed that men in committed relationships, or with young children, have lower levels of testosterone than unpartnered men or men with older or no children. The study described here explored associations between estradiol and progesterone with partnership and parity among women from two different ethnicities: South Asian and white British. We hypothesized that both steroid hormones would be lower among partnered and/or parous women with children ≤3 years old, regardless of ethnicity. In this study we analyzed data from 320 Bangladeshi and British women of European origin aged 18 to 50 who participated in two previous studies of reproductive ecology and health. Levels of estradiol and progesterone were assayed using saliva and/or serum samples and the body mass index calculated from anthropometric data. Questionnaires provided other covariates. Multiple linear regressions were used to analyze the data. The hypotheses were not supported. We argue here that, unlike links between testosterone and male social relationships, theoretical foundations for such relationships with female reproductive steroid hormones are lacking, especially given the primary role of these steroids in regulating female reproductive function. Further longitudinal studies are needed to explore the bases of independent relationships between social factors and female reproductive steroid hormones.

The Current Concept of Paternal Bonding: A Systematic Scoping Review

Bonding is crucial to perinatal mental health. Despite an extensive body of literature on maternal bonding, few studies have focused on paternal bonding. This scoping review aimed to clarify the current state of the concept of paternal-infant/fetus bonding. The eligibility criteria were drawn from the population concept and context elements to answer the following questions: "what is paternal bonding?" and "what are the constructs of the concept of paternal bonding?" The review comprised 39 studies. Paternal bonding was associated with both positive and negative paternal behavior and thought and may be determined based on fathers' beliefs and rearing history. Most studies showed that father-child interaction is one of the factors promoting paternal bonding. However, fathers generally felt more distant from their babies post-delivery than mothers. Only a few studies originally defined paternal bonding; most relied on the definitions of maternal bonding. We found different descriptions lacking consensus. Few studies examined the differences between paternal and maternal bonding. No consensus exists on the concept, constructs, and assessment of paternal bonding. The causal relationship between paternal bonding and other variables is unexplored. Future studies should explore fathers' perspectives and experiences, focusing on the unknown aspects of paternal bonding identified in this review.

Hormonal and behavioral responses to an infant simulator in women with and without children

We investigated the impact of maternal status on hormonal reactivity and behavioral responses to an infant simulator in 117 women (54 primiparous, 63 nulliparous). The amount of affectionate touch and motherese were analyzed as behavioral measures of caregiving. Saliva was collected before and 10 min after interaction with the infant simulator to analyze oxytocin, testosterone, cortisol, and estradiol levels. Nulliparous women also provided information about their fertility motivation. Linear mixed models indicated that greater use of affectionate touch was associated with lower overall testosterone levels. Cortisol decreased in response to the interaction in both groups. In the primiparous group, the amount of affectionate touch associated inversely with cortisol levels, whereas in the nulliparous group such association was not found. Oxytocin or estradiol reactivity to the simulator did not differ between the groups, nor were these hormones associated with behavior. Higher fertility motivation in nulliparous women was related to more motherese, and lower testosterone levels. Our results indicate that the simulator elicits hormonal reactivity both in mothers and nonmothers, but the patterns of associations between caregiving behavior and hormonal levels may be partially different. These results encourage using the infant simulator to explore hormonal processes related to the transition to parenthood.

Maternal hair cortisol concentrations across pregnancy and the early postpartum period in a Puerto Rican sample

OBJECTIVE

Hair cortisol is a noninvasive, long-term biomarker of human stress. Strengths and weaknesses of this biomarker as a proxy measure of perinatal stress are not yet well understood. Hair cortisol data were collected from pregnant women in Puerto Rico to investigate maternal cortisol level variance across pregnancy.

METHODS

In 2017, we recruited 86 pregnant women planning to birth at a large urban hospital. We aimed to collect four hair samples from each participant, one in each trimester and one in the postpartum period.

RESULTS

Median cortisol in the first trimester (n = 82) was 5.7 picograms/milligram (pg/mg) (range: 1.0-62.4). In the second, third, and postpartum periods, the medians were 6.8 pg/mg (1.0-69.5), (n = 46), 20.1 pg/mg (5.6-89.0), (n = 30), and 14.1 pg/mg (1.7-39.8), (n = 9), respectively. These medians disguise a 10-fold and 50-fold variability for two participants. Our sample sizes declined sharply when Hurricane Maria caused major disruptions in services and participants' lives.

CONCLUSION

Maternal hair cortisol concentrations were lower in the first and second trimester than the third trimester and early postpartum period. We also observed a wide range of variation in cortisol levels throughout pregnancy and in the postpartum period.

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.

Early Pup Removal Leads to Social Dysfunction and Dopamine Deficit in Late Postpartum Rats: Prevention by Social Support

Offspring interaction is among the most highly motivated behaviors in maternal mammals and is mediated by mesolimbic dopamine (DA) system activation. Disruption or loss of significant social relationships is among the strongest individual predictors of affective dysregulation and depression onset in humans. However, little is known regarding the effects of disrupted mother–infant attachment (pup removal) in rat dams. Here, we tested the effects of permanent pup removal in rat dams, which were assigned to one of three groups on postpartum day (PD) 1: pups; pups removed, single-housed; or pups removed, co-housed with another dam who also had pups removed; and underwent a behavioral test battery during PD 21–23. In vivo electrophysiological recordings of ventral tegmental area (VTA) DA neurons were performed on PD 22 and 23 in a subset of animals. Pup removal did not impact sucrose consumption or anxiety-like behavior, but increased passive forced swim test (FST) coping responses. Pup-removal effects on social behavior and VTA activity were sensitive to social buffering: only single-housed dams exhibited reduced social motivation and decreased numbers of active DA neurons. Dams that had pups removed and were co-housed did not exhibit changes in social behavior or VTA function. Moreover, no changes in social behavior, FST coping, or VTA activity were found in socially isolated adult virgin females, indicating that effects observed in dams are specific to pup loss. This study showed that deprivation of species-expected social relationships (pups) during the postpartum precipitates an enduring negative affect state (enhanced passive coping, blunted social motivation) and attenuated VTA DA function in the dam, and that a subset of these effects is partially ameliorated through social buffering.

Progesterone - Friend or foe?

Estradiol is the "prototypic" sex hormone of women. Yet, women have another sex hormone, which is often disregarded: Progesterone. The goal of this article is to provide a comprehensive review on progesterone, and its metabolite allopregnanolone, emphasizing three key areas: biological properties, main functions, and effects on mood in women. Recent years of intensive research on progesterone and allopregnanolone have paved the way for new treatment of postpartum depression. However, treatment for premenstrual syndrome and premenstrual dysphoric disorder as well as contraception that women can use without risking mental health problems are still needed. As far as progesterone is concerned, we might be dealing with a two-edged sword: while its metabolite allopregnanolone has been proven useful for treatment of PPD, it may trigger negative symptoms in women with PMS and PMDD. Overall, our current knowledge on the beneficial and harmful effects of progesterone is limited and further research is imperative.

Longitudinal associations between prenatal testosterone and postpartum outcomes in a sample of first-time expectant lesbian couples

Although increasing numbers of gay and lesbian individuals ultimately become parents, the vast majority of research on the transition to parenthood focuses exclusively on heterosexual samples. Even less is known about the physiological implications of this major life transition among those who identify as sexual minorities. The present study begins to redress these gaps in the literature by assessing prospective links between prenatal testosterone, a steroid hormone that is negatively associated with nurturance and caregiving, and postpartum outcomes in a sample of 25 first-time expectant lesbian couples (N = 50 individuals). Consistent with prior work in heterosexual samples, which suggests that lower testosterone promotes both partnering and parenting, we found that, in both partners, lower testosterone during the prenatal period predicted better romantic relationship and parenting outcomes at three-months postpartum (e.g., higher relationship quality, more time spent doing baby care). There was also evidence for dyadic associations; for instance, birth mothers reported more overprotective behavior, and non-birth mothers reported greater commitment, when their female partners had lower testosterone. Together, our findings contribute important new knowledge about the functionality of testosterone in close relationships contexts, including some of the first evidence among sexual minorities.

Changes in prenatal testosterone and sexual desire in expectant couples

During the transition to parenthood (TTP), both women and men report declines in sexual desire, which are thought to reflect an evolutionarily adaptive focus on parenting over mating. New parents also show changes in testosterone, a steroid hormone implicated in both parenting and mating, suggesting that changes in sexual desire may be associated with changes in testosterone. To test these associations, we followed a sample of heterosexual couples expecting their first child across the prenatal period. We examined prenatal changes in testosterone and two forms of sexual desire (solitary, dyadic). Expectant mothers showed prenatal increases in testosterone, and women's higher testosterone was associated with lower dyadic desire. Expectant fathers showed prenatal decreases in testosterone, and declines in men's testosterone were associated with lower dyadic desire. Testosterone was unrelated to men's or women's solitary desire. Our findings provide support for the idea that prenatal changes in testosterone contribute to an evolutionarily adaptive focus on parenting over mating during the TTP.

Mothering revisited: A role for cortisol?

This selective review first describes the involvement of the maternal hypothalamic-pituitary-adrenal (HPA) axis during pregnancy and the postpartum period, and the relation between peripartum HPA axis function and maternal behavior, stress reactivity and emotional dysregulation in human mothers. To provide experimental background to this correlational work, where helpful, animal studies are also described. It then explores the association between HPA axis function in mothers and their infants, under ongoing non-stressful conditions and during stressful challenges, the moderating role of mothers' sensitivity and behavior in the mother-child co-regulation and the effects of more traumatic risk factors on these relations. The overarching theme being explored is that the HPA axis - albeit a system designed to function during periods of high stress and challenge - also functions to promote adaptation to more normative processes, shown in the new mother who experiences both high cortisol and enhanced attraction and attention to and recognition of, their infants and their cues. Hence the same HPA system shows positive relations with behavior at some time points and inverse ones at others. However, the literature is not uniform and results vary widely depending on the number, timing, place, and type of samplings and assessments, and, of course, the population being studied and, in the present context, the state, the stage, and the stress levels of mother and infant.

Hormonal and neural correlates of care in active versus observing poison frog parents

The occasional reversal of sex-typical behavior suggests that many of the neural circuits underlying behavior are conserved between males and females and can be activated in response to the appropriate social condition or stimulus. Most poison frog species (Family Dendrobatidae) exhibit male uniparental care, but flexible compensation has been observed in some species, where females will take over parental care duties when males disappear. We investigated hormonal and neural correlates of sex-typical and sex-reversed parental care in a typically male uniparental species, the Dyeing Poison Frog (Dendrobates tinctorius). We first characterized hormone levels and whole brain gene expression across parental care stages during sex-typical care. Surprisingly, hormonal changes and brain gene expression differences associated with active parental behavior in males were mirrored in their non-caregiving female partners. To further explore the disconnect between neuroendocrine patterns and behavior, we characterized hormone levels and neural activity patterns in females performing sex-reversed parental care. In contrast to hormone and gene expression patterns, we found that patterns of neural activity were linked to the active performance of parental behavior, with sex-reversed tadpole transporting females exhibiting neural activity patterns more similar to those of transporting males than non-caregiving females. We suggest that parallels in hormones and brain gene expression in active and observing parents are related to females' ability to flexibly take over parental care in the absence of their male partners.

Neuroendocrine Effects of Lactation and Hormone-Gene-Environment Interactions

While correlational studies suggest that lactation may confer a certain level of protection from mental illness, this benefit is not uniformly expressed in all women who choose to breastfeed. We propose here that the neuroendocrine "resetting" induced by lactation may predispose toward positive affect states in a subset of hormone-sensitive mothers, with hormone-gene and hormone-environment interactions determining the ultimate psychological outcome. We find evidence to suggest that higher secretion of prolactin/oxytocin as well as lower secretion of vasopression/androgens in lactating mothers may protect against postpartum depression and anxiety, decrease levels of irritability, and optimize stress responses. On the other hand, while the abrupt withdrawal of estradiol/progesterone in the immediate postpartum period tends to be associated with adverse psychological outcomes, the chronic suppression of estrogens/progestogens induced by lactation may have antidepressant and anxiolytic effects over time. Finally, the hypo-cortisolemic state seen in lactating mothers appears to be associated with improved stress reactivity and circadian rhythms. We also discuss hormone-gene and hormone-environment interactions likely to modulate any potential psychological benefits related to lactation and focus on those factors that are either easy to screen for or known to be modifiable. In sum, neuroendocrine alterations induced by lactation may play a key role in determining reproductive psychiatric risk in a subset of hormone-sensitive women. Using these neuroendocrine factors as an individualized index of risk can help in devising targeted programs to support these women in pursuing lactation or, for those not able or willing, accessing psychological interventions in a timely manner.

Developmental responses to early-life adversity: Evolutionary and mechanistic perspectives

Adverse ecological and social conditions during early life are known to influence development, with rippling effects that may explain variation in adult health and fitness. The adaptive function of such developmental plasticity, however, remains relatively untested in long-lived animals, resulting in much debate over which evolutionary models are most applicable. Furthermore, despite the promise of clinical interventions that might alleviate the health consequences of early-life adversity, research on the proximate mechanisms governing phenotypic responses to adversity have been largely limited to studies on glucocorticoids. Here, we synthesize the current state of research on developmental plasticity, discussing both ultimate and proximate mechanisms. First, we evaluate the utility of adaptive models proposed to explain developmental responses to early-life adversity, particularly for long-lived mammals such as humans. In doing so, we highlight how parent-offspring conflict complicates our understanding of whether mothers or offspring benefit from these responses. Second, we discuss the role of glucocorticoids and a second physiological system-the gut microbiome-that has emerged as an additional, clinically relevant mechanism by which early-life adversity can influence development. Finally, we suggest ways in which nonhuman primates can serve as models to study the effects of early-life adversity, both from evolutionary and clinical perspectives.

Evolutionary Theories and Men's Preferences for Women's Waist-to-Hip Ratio: Which Hypotheses Remain? A Systematic Review

Over the last 25 years, a large amount of research has been dedicated to identifying men's preferences for women's physical features, and the evolutionary benefits associated with such preferences. Today, this area of research generates substantial controversy and criticism. I argue that part of the crisis is due to inaccuracies in the evolutionary hypotheses used in the field. For this review, I focus on the extensive literature regarding men's adaptive preferences for women's waist-to-hip ratio (WHR), which has become a classic example of the just-so storytelling contributing to the general mistrust toward evolutionary explanations of human behavior. The issues in this literature originate in the vagueness and incompleteness of the theorizing of the evolutionary mechanisms leading to mate preferences. Authors seem to have rushed into testing and debating the effects of WHR on women's attractiveness under various conditions and using different stimuli, without first establishing (a) clear definitions of the central evolution concepts (e.g., female mate value is often reduced to an imprecise concept of "health-and-fertility"), and (b) a complete overview of the distinct evolutionary paths potentially at work (e.g., focusing on fecundability while omitting descendants' quality). Unsound theoretical foundations will lead to imprecise predictions which cannot properly be tested, thus ultimately resulting in the premature rejection of an evolutionary explanation to human mate preferences. This paper provides the first comprehensive review of the existing hypotheses on why men's preferences for a certain WHR in women might be adaptive, as well as an analysis of the theoretical credibility of these hypotheses. By dissecting the evolutionary reasoning behind each hypothesis, I show which hypotheses are plausible and which are unfit to account for men's preferences for female WHR. Moreover, the most cited hypotheses (e.g., WHR as a cue of health or fecundity) are found to not necessarily be the ones with the strongest theoretical support, and some promising hypotheses (e.g., WHR as a cue of parity or current pregnancy) have seemingly been mostly overlooked. Finally, I suggest some directions for future studies on human mate choice, to move this evolutionary psychology literature toward a stronger theoretical foundation.

Maternal major depression and synchrony of facial affect during mother-child interactions

Maternal history of Major Depressive Disorder (MDD) dramatically increases children's risk for developing depression, highlighting the critical need for further research on the specific processes involved in the intergenerational transmission of depression. Although previous research suggests that maternal depression may adversely affect the quality of mother-child interactions, less is known about the role of maternal MDD in the moment-to-moment changes in affect that occur during these interactions. The goal of this project, therefore, was to examine synchrony of facial displays of affect during a positive (Vacation Planning) and a negative (Issues Discussion) mother-child interaction, and how this synchrony may be impacted by maternal history of MDD. In doing so, we examined both concurrent and lagged synchrony of facial affect. We recruited 341 mother-child dyads (child average age = 9.30 years; 50.1% girls; 71.6% Caucasian) with and without a maternal history of MDD. Facial electromyography (EMG), continuously recorded during those tasks, was used to index mother and child facial affect. We found that a maternal history of MDD was associated with reduced concurrent synchrony and lagged synchrony (mother facial affect predicting changes in child facial affect) of positive affect during Vacation Planning. Reduced concurrent mother-child synchrony of positive affect during the discussion was also associated with an increase in child self-reported sad affect from before to after the discussion. These findings provide promising initial evidence for how the dynamic exchange of positive affect during mother-child interactions may be disrupted in families with maternal MDD history. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Resilience priming: Translational models for understanding resiliency and adaptation to early life adversity

Despite the increasing attention to early life adversity and its long-term consequences on health, behavior, and the etiology of neurodevelopmental disorders, our understanding of the adaptations and interventions that promote resiliency and rescue against such insults are underexplored. Specifically, investigations of the perinatal period often focus on negative events/outcomes. In contrast, positive experiences (i.e. enrichment/parental care//healthy nutrition) favorably influence development of the nervous and endocrine systems. Moreover, some stressors result in adaptations and demonstrations of later-life resiliency. This review explores the underlying mechanisms of neuroplasticity that follow some of these early life experiences and translates them into ideas for interventions in pediatric settings. The emerging role of the gut microbiome in mediating stress susceptibility is also discussed. Since many negative outcomes of early experiences are known, it is time to identify mechanisms and mediators that promote resiliency against them. These range from enrichment, quality parental care, dietary interventions and those that target the gut microbiota.

The HPA Axis During the Perinatal Period: Implications for Perinatal Depression

The transition to motherhood is characterized by some of the most pronounced endocrine changes a woman will experience in her lifetime. Unfortunately, matrescence is also a time in a woman's life when she is most susceptible to mental illness such as perinatal depression. A growing body of research has aimed to determine how key endocrine systems, such as the hypothalamic-pituitary-adrenal (HPA) axis, are involved in the dysregulation of perinatal mental health. However, very little research has consistently linked perinatal changes in the HPA axis with maternal mental illness. Therefore, the aims of this mini review are to: (i) clearly summarize the normative changes in the HPA axis that occur during pregnancy and the postpartum period; (ii) summarize what we know about the HPA axis in perinatal depression, and (iii) propose key areas for future research. Understanding physiological biomarkers that can predict which women are at risk for perinatal mood disorders will lead to better tools for treating, and ultimately preventing, these debilitating disorders, improving the health of mother, child, and family.

Maternal programming: Application of a developmental psychopathology perspective

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

Effect of maternal depression and anxiety on mother's perception of child and the protective role of social support

OBJECTIVE

The purpose of this study was to investigate the impact of postpartum depressive and anxiety symptoms on maternal perception of the infant and the protective role of social support.

BACKGROUND

Adverse effects of perinatal depression on mother-child interaction are well documented; however, the role of maternal perception has not been examined.

METHODS

We used the data of 431 women enrolled in a prospective study in a single maternity unit. Depressive and anxiety symptoms were measured using the Edinburgh Postnatal Depression Scale (EPDS), the State Trait Anxiety Inventory (STAI), and the mother's perception of infant with the Mother's Object Relation Scale (MORS). We used Multidimensional Scale of Perceived Social Support (MSPSS) in order to measure social support.

RESULTS

Depressive and anxiety symptoms were positively associated to less positive emotions and a more dominant attitude of child as perceived by mothers. This association was even more significant in the case of trait anxiety. Perceived social support has been found to be a protective factor which was able to reduce this tendency.

CONCLUSION

The findings have potential implications for our understanding of the impact of maternal depressive and anxiety symptoms on the developing mother-infant relationship.

Role of oxytocin in parental behaviour

Both animal and human studies have provided conclusive evidence that oxytocin (OXT) acts in the brain (eg, medial preoptic area, ventral tegmental area, nucleus accumbens) to promote parental behaviour under different reproductive and physiological conditions. OXT appears to accelerate and strengthen the neural process that makes newborns attractive or rewarding. Furthermore, OXT reduces stress/anxiety and might improve mood and well being, resulting in indirect benefits for parents. However, OXT also plays a role in the development of species reproductive and social strategies, making some species or individuals more prone to display caring activities in nonreproductive contexts. There are important differences in the development of the OXT system and its regulation by gonadal hormones that can make individuals or species very different. Those intra- and interspecific differences in the OXT system have been associated with differences in parental behaviour. For example, differences in OXT levels in body fluids and genetic variants for the OXT and OXT receptor genes have been associated with variability in parental mood and behaviour in humans. Thus, OXT has received much attention as a potential therapeutic agent for affective, emotional and behavioural problems. Despite many preliminary studies indicating promising findings, several unknown aspects of the OXT system remain to be addressed before we can achieve a complete understanding of its function in the brain. The enormous interest that this area of study has attracted in the last decade will likely continually contribute to advancing our understanding of the role of OXT in parental behaviour and other behavioural and physiological functions.

Maternal mental health during the neonatal period: Relationships to the occupation of parenting

PURPOSE

To (1) examine the extent of a range of early mental health challenges in mothers with a very preterm infant hospitalized in the NICU and mothers of full-term infants, (2) identify family social background and infant medical factors associated with higher levels of maternal psychological distress, and (3) assess the relationship between maternal psychological distress and maternal perceptions of the parenting role, parenting confidence and NICU engagement.

METHODS

At hospital discharge 37 mothers of very preterm infants (≤32 weeks gestation) and 47 mothers of full-term infants (≥37 weeks gestation) completed structured assessments of their psychological wellbeing and transition to parenting. Mothers of very preterm infants were also questioned about their NICU visitation and involvement in infant care.

RESULTS

Sixty-four percent (n = 54) of mothers experienced psychological distress (n = 26, 70% of preterm; n = 28, 60% of full-term). Lower infant birthweight was associated with maternal psychological distress (p = .03). Mothers of very preterm infants had significantly more psychological distress related to having a Cesarean section delivery (p = .02). Higher levels of psychological distress were associated with lower levels of parenting confidence in mothers of both very preterm and full-term infants (p < .02).

CONCLUSION

Although parents of very preterm infants have higher rates of maternal mental health challenges, mothers of full-term infants at high social risk are also impacted.

Sex differences in depression during pregnancy and the postpartum period

Women have a lifetime risk of major depression double that of men but only during their reproductive years. This sex difference has been attributed partially to activational effects of female sex steroids and also to the burdens of pregnancy, childbirth, and parenting. Men, in contrast, have a reproductive period difficult to delineate, and research on the mental health of men has rarely considered the effects of fatherhood. However, the couple goes through a number of potentially stressing events during the reproductive period, and both mothers and fathers are at risk of developing peripartum depression. This Review discusses the literature on maternal and paternal depression and the endocrine changes that may predispose a person to depression at this stage of life, with specific focus on the hypothalamus–pituitary axis, oxytocin, and testosterone levels in men. Important findings on sex differences in the neural correlates of maternal and paternal behavior have emerged, highlighting the relevance of the emotional brain in mothers and the sociocognitive brain in fathers and pointing toward the presence of a common parents' brain. Additionally, sex differences in neurogenesis and brain plasticity are described in relation to peripartum depression. © 2016 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc.

Testosterone, oxytocin, and the development of human parental care

The steroid testosterone (T) and neuropeptide oxytocin (OT) have each been implicated in the development of parental care in humans and animals, yet very little research addressed the interaction between these hormones at the transition to parenthood in mothers and fathers. One hundred and sixty mothers and fathers (80 couples) were visited 1 and 6months after the birth of their first child, plasma OT and T were assayed at each time-point, and interactions between each parent and the infant were observed and micro-coded for two key parental behaviors; affectionate touch and parent-infant synchrony. T showed gender-specific effects. While paternal T was individually stable across the first six months of parenting and predicted lower father-infant synchrony, maternal T was neither stable nor predictive of maternal behavior. An interaction of OT and T showed that T has complex modulatory effects on the relations of OT and parenting. Slope analysis revealed that among fathers, only when T was high (+1SD), negative associations emerged between OT and father affectionate touch. In contrast, among mothers, the context of high T was related to a positive association between OT and maternal touch. Our findings, the first to test the interaction of OT and T in relation to observed maternal behavior, underscore the need for much further research on the complex bidirectional effects of steroid and neuropeptide systems on human mothering and fathering.

The effect of infant vocalization in alloparental responsiveness of common marmosets (Callithrix jacchus)

Among mammals, alloparental care can be influenced by hormones as well as by previous experience and sensory stimuli from the infants, such as sight and sound, smell, and physical contact with the infant. To determine the responsiveness of common marmoset (Callithrix jacchus) nonreproductive females and males with and without previous experience in caretaking to infant sensory cues, we exposed 12 females and 12 males to vocalization recordings for 10 min under two conditions: (1) exposure to adult conspecific vocalization recordings, and (2) exposure to infant vocalization recordings. We recorded the frequency of approach toward the sound source, the time spent near it and locomotion frequency of males and females in the cage under both conditions. Blood samples were collected after each test for cortisol measuring by EIA method. The infant vocalization affects the behavioral and hormonal responses of males and females of common marmosets. The animals approached and spent more time near the sound source and showed an increase in locomotion during infant vocalization exposure compared to the adult vocalization. However, there was no significant difference in the behavioral response of animals when previous experience and the sex were taken into account. In both sexes, cortisol levels were significantly higher following infant vocalization exposure compared to the adult vocalization. These findings suggest that the infant vocalization appears to be an effective cue that facilitates the approach of the caregiver and maintaining their responsiveness and that the cortisol seems to be important for alertness to sensory stimuli, modulating their motivation to interact with the infant.

Fathers' decline in testosterone and synchrony with partner testosterone during pregnancy predicts greater postpartum relationship investment

The transition to parenthood has been associated with declines in testosterone among partnered fathers, which may reflect males' motivation to invest in the family. Moreover, preliminary evidence has found that couples show correlations in hormone levels across pregnancy that may also be linked to fathers' preparation for parenthood. The current study used repeated-measures sampling of testosterone across pregnancy to explore whether fathers' change in T, and correlations with mothers' T, were associated with fathers' and mothers' postpartum investment. In a sample of 27 couples (54 individuals) expecting their first child, both parents' salivary testosterone was measured multiple times across pregnancy. At approximately 3.5months postpartum, participants rated their investment, commitment, and satisfaction with their partner. A multilevel model was used to measure change in testosterone over time and associations between mother and father testosterone. Fathers who showed stronger declines in T across pregnancy, and stronger correlations with mothers' testosterone, reported higher postpartum investment, commitment, and satisfaction. Mothers reported more postpartum investment and satisfaction if fathers showed greater prenatal declines in T. These results held even after controlling for paternal investment, commitment, and satisfaction measured prenatally at study entry. Our results suggest that changes in paternal testosterone across pregnancy, and hormonal linkage with the pregnant partner, may underlie fathers' dedication to the partner relationship across the transition to parenthood.

The neurobiological causes and effects of alloparenting

Alloparenting, defined as care provided by individuals other than parents, is a universal behavior among humans that has shaped our evolutionary history and remains important in contemporary society. Dysfunctions in alloparenting can have serious and sometimes fatal consequences for vulnerable infants and children. In spite of the importance of alloparenting, they still have much to learn regarding the underlying neurobiological systems governing its expression. Here, they review how a lack of alloparental behavior among traditional laboratory species has led to a blind spot in our understanding of this critical facet of human social behavior and the relevant neurobiology. Based on what is known, they draw from model systems ranging from voles to meerkats to primates to describe a conserved set of neuroendocrine mechanisms supporting the expression of alloparental care. In this review we describe the neurobiological and behavioral prerequisites, ontogeny, and consequences of alloparental care. Lastly, they identified several outstanding topics in the area of alloparental care that deserve further research efforts to better advance human health and wellbeing. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 214-232, 2017.

Prospective and dyadic associations between expectant parents' prenatal hormone changes and postpartum parenting outcomes

During the transition to parenthood, both men and women experience hormone changes that are thought to promote parental care. Yet very few studies have explicitly tested the hypothesis that prenatal hormone changes are associated with postpartum parenting behavior. In a longitudinal study of 27 first-time expectant couples, we assessed whether prenatal hormone changes were moderated by self- and partner-reported parenting outcomes at 3 months postpartum. Expectant fathers showed prenatal declines in testosterone and estradiol, and larger declines in these hormones were associated with greater contributions to household and infant care tasks postpartum. Women whose partners showed larger testosterone declines also reported receiving more support and more help with household tasks. Expectant mothers showed prenatal increases in testosterone and estradiol, and larger increases in these hormones were associated with lower partner-rated support. Together, our findings provide some of the first evidence that prenatal hormone changes may indeed be functional and that the implications of these changes may be detectable by co-parents.

Contributions of Psychophysiology to Research on Adult Attachment: Review and Recommendations

Despite the increasing use of psychophysiological measures to investigate social and interpersonal phenomena, few studies of adult romantic attachment have taken advantage of this approach. In this article I argue for a biologically-specific, theory-based integration of psychophysiological measures into adult attachment research. This approach would help elucidate the normative psychobiological properties of the attachment system, which have received little study in humans. Specifically, it would allow researchers to test targeted hypotheses regarding affect and arousal regulation in attachment relationships. I provide a general introduction to 2 biological systems that hold particular promise for adult attachment research: the parasympathetic branch of the autonomic nervous system and the hypothalamic-pituitary-adrenocortical axis of the endocrine system. I highlight the relevance of these systems for attachment phenomena and review findings from selected social psychophysiological research. I conclude by outlining a tentative theoretical model of the psychobiology of adult attachment and identifying specific directions for future research.

Psychobiology and Social Psychology: Past, Present, and Future

Social psychology and psychobiology have a rich historicalconnection, although over the last half century these two disciplineshave seemingly become estranged. To a significant extent, that alienation arose from an archaic and nonviable model of behavioral biology that retarded the development of both disciplines. With the emergence of modern biological perspectives, this impediment no longer limits fruitful collaborations among social psychologists and psychobiologists. Indeed, some of the most exciting contemporary developments are emerging from the areas of social neuroscience, cognitive neuroscience, and behavioral neuroscience. We review the history of links between social psychology and psychobiology, the factors that led to the segregation of these subdisciplines, and the modern biological perspectives that provide the basis for reintegration of these disciplines.

Regulatory role of prolactin in paternal behavior in male parents: A narrative review

In all mammalian species, a combination of neuroendocrine and experiential factors contributes to the emergence of remarkable behavioral changes observed in parental behavior. Yet, our understanding of neuroendocrine bases of paternal behavior in humans is still preliminary and more research is needed in this area. In the present review, the authors summarized hormonal bases of paternal behavior in both human and nonhuman mammalian species and focused on studies on the regulatory role of prolactin in occurrence of paternal behavior. All peer-reviewed journal articles published before 2015 for each area discussed (parental brain, hormonal bases of maternal behavior, hormonal bases of paternal behavior and the role of prolactin in regulation of paternal behavior in nonhuman mammalian species, hormonal bases of paternal behavior and the role of prolactin in regulation of paternal behavior in humans) were searched by PubMed, Medline, and Scopus for original research and review articles. Publications between 1973 and 2015 were included. Similar to female parents, elevated prolactin levels in new fathers most probably contribute to child-caring behavior and facilitate behavioral and emotional states attributed to child care. Moreover, elevated parental prolactin levels after childbirth decrease the parents' libidos so that they invest more in parental care than in fertility behavior. According to the available clinical studies, elevation in the amounts of prolactin levels after childbirth in male parents are probably associated with paternal behavior observed in humans.

The endocrinology of human caregiving and its intergenerational transmission

Variation in the quality of parental care has a tremendous impact on a child's social–emotional development. Research investigating the predictors of this variability in human caregiving behavior has mostly focused on learning mechanisms. Evidence is currently accumulating for the complementary underlying role of steroid hormones and neuropeptides. An overview is provided of the hormones and neuropeptides relevant for human caregiving behavior. Then the developmental factors are described that stimulate variability in sensitivity to these hormones and neuropeptides, which may result in variability in the behavioral repertoire of caregiving. The role of genetic variation in neuropeptide and steroid receptors, the role of testosterone and oxytocin during fetal development and parturition, and the impact of experienced caregiving in childhood on functioning of the neuroendocrine stress and oxytocin system are discussed. Besides providing a heuristic framework for further research on the ontogenetic development of human caregiving, a neuroendocrine model is also presented for the intergenerational transmission of caregiving practices. Insight into the underlying biological mechanisms that bring about maladaptive caregiving behavior, such as neglect and insensitive parenting, will hopefully result in more efficient approaches to reduce the high prevalence of such behavior and to minimize the impact on those affected.

Paternal and Maternal Testosterone in Parents of NICU Infants Transitioning Home

Lower testosterone during the transition to new parenthood is considered beneficial to help parents better engage with their infants. No data currently exist studying salivary testosterone of parents with infants in neonatal intensive care units (NICUs) during the transition to home. We examine testosterone levels for parents of very low-birth-weight infants, including links between salivary testosterone and infant factors (such as breast-feeding), psychosocial stress, and changes over time.Testosterone salivary samples were assayed after self-collection by 86 parents (43 fathers and 43 mothers) with NICU infants at wakeup and bedtime prior to discharge and at 3 additional times at home. Self-reported survey measures, including psychosocial reports, were also collected at these times.Using multilevel modeling approaches, we report significant associations between paternal testosterone by time and psychosocial adjustment and between both paternal and maternal testosterone and infant feeding mode (P < .05). Results were significant after accounting for covariates. Our study is the first to examine the time course of diurnal testosterone for parents of premature infants over the transition home; as such, we suggest further research into better understanding parental physiology in this vulnerable parent population.

Gestational hormone profiles predict human maternal behavior at 1-year postpartum

In many non-human species, including primates, gestational reproductive hormones play an essential role in the onset of maternal motivation and behaviors. We investigated the associations between prepartum estradiol and progesterone and maternal behavior at 1-year postpartum in 177 women. Blood was obtained at five gestational time points and an index of quality of maternal care was determined using a well-validated mother-child interaction protocol. Women who exhibited higher quality maternal care at 1-year postpartum were characterized by unique gestational profiles of estradiol, progesterone and the estrogen to progesterone ratio; specifically by slower accelerations and levels of these hormone trajectories beginning in midgestation. Further, it appeared that both fetal sex and parity moderated these findings, with first time mothers and mothers of females showing stronger associations. In sum, these data document persisting associations between prepartum hormone profiles and human maternal behavior. More broadly, these findings add to the growing literature highlighting the perinatal period as one of critical neurodevelopment in the lifespan of the human female.

Psychobiological influences on maternal sensitivity in the context of adversity

This study evaluated prospective longitudinal relations among an index of poverty-related cumulative risk, maternal salivary cortisol, child negative affect, and maternal sensitivity across the first 2 postpartum years. Participants included 1,180 biological mothers residing in rural and predominantly low-income communities in the United States. Multilevel growth curve analyses indicated that an index of cumulative risk was positively associated with maternal cortisol across the postpartum (study visits occurring at approximately 7, 15, and 24 months postpartum) over and above effects for African American ethnicity, time of day of saliva collection, age, parity status, having given birth to another child, contraceptive use, tobacco smoking, body mass index, and breastfeeding. Consistent with a psychobiological theory of mothering, maternal salivary cortisol was negatively associated with maternal sensitivity observed during parent-child interactions across the first 2 postpartum years over and above effects for poverty-related cumulative risk, child negative affect, as well as a large number of covariates associated with cortisol and maternal sensitivity. Child negative affect expressed during parent-child interactions was negatively associated with observed maternal sensitivity at late (24 months) but not early time points of observation (7 months) and cumulative risk was negatively associated with maternal sensitivity across the postpartum and this effect strengthened over time. Results advance our understanding of the dynamic, transactional, and psychobiological influences on parental caregiving behaviors across the first 2 postpartum years. (PsycINFO Database Record

The more things change, the more things stay the same: maternal attitudes 3 to 18 months postpartum

AIM

Becoming a parent precipitates changes in new mothers' psychological and social domains. Previous literature has focused exclusively on pregnancy and the early postpartum, but parenting is an evolving process, necessitating adaption to changing circumstances. We extended previous literature and investigate the changes in the postpartum from 3 to 18 months that occur in maternal attitudes.

METHODS

Using the Childbearing Attitudes Questionnaire, we collected data on mothers' ratings of maternal worries, self-efficacy, mother-infant bonding, relationship with the partner and interest in sex (n = 171 women). Data were analysed with a latent growth curve.

RESULTS

Results demonstrated stability in all maternal attitudes after 3 months postpartum. Further, different maternal attitudes are affected by different variables. Maternal worries and self-efficacy are associated with parity, postpartum depression and child temperament. Interestingly, a negative evaluation of the relationship with the partner was only associated with breastfeeding status, while interest in sex was associated with parity, socio-economic status (SES) and depressive symptoms.

CONCLUSION

Despite general stability, different maternal attitudes related to different sets of variables. These patterns of attitudes in relation to relevant variables are discussed in terms of the literature on self-efficacy and gender roles, with important implications for clinical interventions.

Biological Bases of Maternal Attachment

In recent years, there has been growing interest in investigating the processes affecting caregiving behavior. Recent studies of human and nonhuman primates have suggested that hormones can account, at least in part, for changes in caregiving motivation during pregnancy and the postpartum period and for variability in caregiving motivation and behavior among individuals. Although hormones may not be the primary determinants of caregiving, future research cannot afford to overlook the contribution that biological processes can make to normative and pathological attachment and parenting.

Breastfeeding, Bed-Sharing, and Maternal Cortisol

Prior studies have found that close mother-child sleep proximity helps increase rates of breastfeeding, and breastfeeding itself is linked to better maternal and infant health. In this study, we examine whether breastfeeding and infant bed-sharing are related to daily rhythms of the stress-responsive hormone cortisol. We found that bed-sharing was related to flatter diurnal cortisol slopes, and there was a marginal effect for breastfeeding to predict steeper cortisol slopes. Furthermore, mothers who breastfeed but do not bed-share had the steepest diurnal cortisol slopes, whereas mothers who bed-shared and did not breastfeed had the flattest slopes (P < .05). These results were significant after controlling for subjective sleep quality, perceived stress, depression, socioeconomic status, race, and maternal age. Findings from this study indicate that infant parenting choices recommended for infants (breastfeeding and separate sleep surfaces for babies) may also be associated with more optimal stress hormone profiles for mothers.