Associations between stress exposure and new mothers' brain responses to infant cry sounds

The parental brain, perinatal mental illness, and treatment: A review of key structural and functional changes

The transition to parenthood is perhaps the only time in adult life when the brain changes to such a significant degree in such a short period, particularly in birthing parents. It is also a time when there is an increased risk of developing a mental illness, which may be due, in part, to the increased neuroplasticity. Thus, we must develop interventions and treatments that support parents and promote parental brain health. This review will highlight key findings from current research on how human brain structure and function are modified with 1) the transition to parenthood, 2) parenting stress and perinatal mental illness, and 3) treatments aimed at promoting perinatal mental health. The focus will be on birthing parents and mothers, but brain changes in non-birthing parents will also be discussed. Improvements in our understanding of the parental brain, in health and with illness, will promote the well-being of generations to come.

Building resilience in families experiencing homelessness through integration of health, parenting and child development programs

Children who experience homelessness are vulnerable to mental health problems, developmental delays and lower academic achievement. Research suggests that parental health literacy, sensitive parenting behaviour and child self-regulation are modifiable mechanisms that might enhance children's resilience to adversities associated with homelessness, yet empirical evidence on implementing such interventions in shelter settings is limited. Through a coordinated academic-community partnership, this study aimed to examine the (1) feasibility of conducting an integrated health approach in shelter settings and (2) the effectiveness of separate interventions on child and parent outcomes. Results are discussed in terms of best practices in shelter settings and building resilience in families experiencing homelessness with young children.

Neural processing of cry sounds in the transition to fatherhood: Effects of a prenatal intervention program and associations with paternal caregiving

This study examined whether neural processing of infant cry sounds changes across the transition to fatherhood (i.e., from the prenatal to postnatal period), and examined whether an interaction-based prenatal intervention modulated these changes. Furthermore, we explored whether postnatal activation in brain regions showing transition or intervention effects was associated with sensitive care and involvement. In a randomized controlled trial, 73 first-time expectant fathers were enrolled, of whom 59 had at least 1 available fMRI scan. Intervention and transition effects on cry processing were analyzed in the amygdala and superior frontal gyrus (SFG) using linear mixed effect models with all available data and with intent-to-treat analyses. Further, exploratory whole-brain analyses were performed. ROI analyses suggest that the transition to fatherhood is characterized by decreasing activation in response to cry vs control sounds in the amygdala but not SFG. Exploratory whole-brain analyses also show a decrease in activation over the transition to fatherhood in the sensorimotor cortex, superior lateral occipital cortex, hippocampus, and regions of the default mode network. In the putamen and insula, larger decreases were found in fathers with more adverse childhood caregiving experiences. In regions showing transitional changes, higher postnatal activation was associated with more concurrent parenting sensitivity. No effects of the intervention were found. The decrease in activation from the pre- to postnatal period may reflect fathers' habituation to cry sounds over repeated exposures. The positive association between postnatal neural activation and paternal sensitive care suggest that continued sensitivity to cry sounds may be conducive to parenting quality.

Neural correlates of inhibitory control in the context of infant cry and paternal postpartum mental health

BACKGROUND

Inhibitory control, a form of self-regulation, may support sensitive parenting, but has been understudied in new fathers despite their pronounced risk for stress and mental health challenges.

METHODS

This study probed the neural correlates of inhibitory control and its associations to first-time fathers' postpartum mental health, focusing on depressive symptoms, state anxiety, and perceived stress. Six months after their child's birth, 38 fathers self-reported on their mood, anxiety, and stress, and performed a Go/No-Go fMRI task while listening to three sets of sounds (infant cry, pink noise, and silence).

RESULTS

Fathers' behavioral inhibition accuracy was consistent across the sound conditions, but their patterns of neural activation varied. Compared to the pink noise condition, fathers showed heightened engagement in prefrontal regulatory regions when self-regulating during the infant cry and silent conditions. When examining correct trials only, results in visual motor area and primary somatosensory cortex emerged only for infant cry and not for pink noise and silence. Moreover, fathers reporting higher levels of postpartum depression, state anxiety, and perceived stress showed greater activation in prefrontal regions when inhibiting during infant cry or silence.

CONCLUSION

This study is the first to underscore the complex interplay between the neural mechanisms related to inhibitory control and postpartum mental health and stress across varied auditory context, laying the groundwork for future research.

Protective role of parenthood on age-related brain function in mid- to late-life

The experience of parenthood can profoundly alter one's body, mind, and environment, yet we know little about the long-term associations between parenthood and brain function and aging in adulthood. Here, we investigate the link between number of children parented (parity) and age on brain function in 19,964 females and 17,607 males from the UK Biobank. In both females and males, increased parity was positively associated with functional connectivity, particularly within the somato/motor network. Critically, the spatial topography of parity-linked effects was inversely correlated with the impact of age on functional connectivity across the brain for both females and males, suggesting that a higher number of children is associated with patterns of brain function in the opposite direction to age-related alterations. These results indicate that the changes accompanying parenthood may confer benefits to brain health across the lifespan, highlighting the importance of future work to understand the associated mechanisms.

Age and parous-experience dependent changes in emotional contagion for positive infant sounds

Introduction

Emotional contagion is achieved by inferring and emotionally resonating with other persons' feelings. It is unclear whether age-related changes in emotional contagion for infant sounds are modulated by the experience of childbirth or childcare. This study aims to evaluate changes in inference and emotional resonance for positive and negative infant sounds (laughter and crying) among women, based on age and parous experience.

Methods

A total of 241 women (60 young nulliparous, 60 young parous, 60 old nulliparous, and 61 old parous) completed a web-based questionnaire. After listening to three types of infant sounds (laughter, cooing, and crying), participants responded with their valence for hearing infant sounds and estimated infant valence on an 11-point Likert scale.

Results

The analysis for emotional resonance revealed that the correlation coefficient between self and estimated infant valences was greater in young parous and old nulliparous women than in young nulliparous women, in laughter and cooing sounds. However, correlation coefficients for crying did not differ among any of the four groups.

Conclusion

The degree of emotional resonance for infant valence increased depending on age and parous-experience for positive infant sounds.

Neural correlates of altered emotional responsivity to infant stimuli in mothers who use substances

Mothers who use substances during pregnancy and postpartum may have altered maternal behavior towards their infants, which can have negative consequences on infant social-emotional development. Since maternal substance use has been associated with difficulties in recognizing and responding to infant emotional expressions, investigating mothers' subjective responses to emotional infant stimuli may provide insight into the neural and psychological processes underlying these differences in maternal behavior. In this study, 39 mothers who used substances during the perinatal period and 42 mothers who did not underwent functional magnetic resonance imaging while viewing infant faces and hearing infant cries. Afterwards, they rated the emotional intensity they thought each infant felt ('think'-rating), and how intensely they felt in response to each infant stimulus ('feel'-rating). Mothers who used substances had lower 'feel'-ratings of infant stimuli compared to mothers who did not. Brain regions implicated in affective processing (e.g., insula, inferior frontal gyrus) were less active in response to infant stimuli, and activity in these brain regions statistically predicted maternal substance-use status. Interestingly, 'think'-ratings and activation in brain regions related to cognitive processing (e.g., medial prefrontal cortex) were comparable between the two groups of mothers. Taken together, these results suggest specific neural and psychological processes related to emotional responsivity to infant stimuli may reflect differences in maternal affective processing and may contribute to differences in maternal behavior in mothers who use substances compared to mothers who do not. The findings suggest potential neural targets for increasing maternal emotional responsivity and improving child outcomes.

Implementing Guidelines for NICU Parent Presence: Effects on Parent and Infant Stress

BACKGROUND

Relationships between parents and infants are essential for mitigating stressors encountered in neonatal intensive care units (NICUs) and are supported by parent presence and engagement.

PURPOSE

The purpose of this study was to compare NICU parent and infant outcomes pre- and postimplementation of an intervention aimed at increasing parent presence and engagement in the NICU. This family-centered care intervention consisted of communicating specific guidelines for parent presence.

METHODS

Data related to parent presence, skin-to-skin care, and breastfeeding; parental stress; infant outcomes including weight gain, length of stay, feeding status at discharge, and stress; and unit-level outcomes were collected from a convenience sample of 40 NICU families recruited preimplementation and compared with data for 38 NICU families recruited postimplementation of specific guidelines for parent presence. To establish comparability of groups, infants were assigned scores using the Neonatal Medical Index.

RESULTS

Parent presence, engagement in skin-to-skin care, and breastfeeding rates were not significantly different between groups. Stress-related outcomes were significantly decreased in NICU mothers, fathers, and infants, and infant feeding outcomes were improved in the postintervention group.

CONCLUSIONS

Specific guidelines for parent presence may represent an invitation for parents to engage with their NICU infants and may positively impact parent and infant stress.

Infant colic and abdominal pain; associations with infant multimorbidity and maternal perceived stress up to 3 months postpartum-A cross-sectional/cohort study in the PreventADALL study

AIMS AND OBJECTIVES

The primary aim was to explore whether infants with pain symptoms (colic, abdominal pain and visit to healthcare provider with pain or other discomforts) had increased multimorbidity (common infections, eczema and food sensitivity) compared with infants without these conditions. Secondarily, we aimed to determine whether infant pain symptoms were associated with maternal perceived stress in pregnancy and 3 months postpartum.

BACKGROUND

Infant colic and abdominal pain are common concerns in early infancy. Nevertheless, to our knowledge, little research exists on the relationship between infant pain and common infant infections, eczema and food sensitization as comorbidities, and the impact of infant pain on the development of maternal perceived stress from pregnancy to infancy is inconsistent.

DESIGN

This study was cross-sectional and partly prospective.

METHODS

The sample consisted of mother-infant pairs (N = 1852); information regarding infant pain and multimorbidity was collected from the 3-month questionnaire and postpartum visits in the PreventADALL prospective cohort study. Chi-square tests and regression analyses were conducted. The STROBE checklist was followed.

RESULTS

Our results showed a statistically significant higher proportion of respiratory and other infections in infants with pain symptoms. The odds of infant pain were higher for infants with multimorbidity compared to those with no comorbidity. Mothers of infants with colic and of infants visiting healthcare with pain and other discomforts reported statistically significant higher perceived stress by 3 months compared with mothers of infants with no reported pain.

CONCLUSION

Our results indicate an association between infant pain symptoms and the presence of infections. Mothers of infants with colic and visiting healthcare had higher perceived stress compared to the no pain group.

IMPLICATIONS FOR PRACTICE

Our study indicates that infant pain is associated with infant multimorbidity and maternal perceived stress, which may be useful when planning diagnostic, treatment and coping strategies in infant and family care.

PATIENT OR PUBLIC CONTRIBUTION

The PreventADALL is a collaborative study with governmental and patient organisation representation. Selected infants with parents were also contributing during calibrating courses on eczema assessment for the data collectors.

TRIAL REGISTRATION

The study was approved by the Regional Committee in Norway (2014/518) and Sweden (2014/2242-31/4) and registered at clinicaltrial.gov (NCT02449850). Link for clinical trials: https://clinicaltrials.gov/ct2/show/NCT02449850.

Cannabis use during pregnancy and hemodynamic responses to infant cues in pregnancy: an exploratory study

Introduction

Cannabis is one of the most commonly used substances during pregnancy and has the potential to negatively impact parent-infant relationships. The prefrontal cortex (PFC) response to infant cues during pregnancy has been associated with subsequent positive parenting behaviors. However, PFC activation is altered in individuals who use cannabis. As the potency of cannabis has changed over the years, little is known about the specific role of cannabis use on gestational parent brain responses to infant cues.

Materials and methods

Using functional Near-Infrared Spectroscopy (fNIRS) in the second trimester of pregnancy, we measured hemodynamic responses to an infant cry task and an infant faces task among individuals who were using cannabis (N = 14) and compared them with those who were not using cannabis (N = 45). For the infant cry task, pregnant individuals listened to cry sounds and matched white noise. For the infant faces task, they viewed happy, sad, and neutral faces.

Results

There was no significant difference between the two groups after adjusting for multiple comparisons. Without adjusting for multiple comparisons, we found preliminary evidence for the differences in the dorsomedial PFC associated with heightened response to infant cry among individuals who use cannabis. The groups were also different in the dorsolateral PFC associated with decreased response to infant sad faces among individuals who use cannabis.

Discussion

Our preliminary data suggests that cannabis use during pregnancy was associated with brain activation in the regions involved in the emotional regulation and information processes. However, the results did not survive after adjustment for multiple comparisons, thus future research with larger sample sizes is needed to confirm potential differences in brain function among cannabis-using pregnant individuals.

Infant crying predicts real-time fluctuations in maternal mental health in ecologically valid home settings

Exposure to infant crying is a well-established predictor of mothers' mental health. However, this association may reflect many potential mechanisms. Capturing dynamic fluctuations in mothers' states simultaneously with caregiving experiences is necessary to identify the real-time processes influencing mental health. In this study, we leveraged ecological momentary assessments (EMAs) and infant-worn audio recorders to capture variability in mothers' mental health symptoms and their exposure to infant crying over one week in a racially and socio-economically diverse urban North-American sample (N = 53). We use multilevel modeling to characterize within- and between-person effects of crying on maternal negative affect and symptoms of depression and anxiety. Within participants, when infants cried more than average in the 10 min, 1 hr, and 8 hr prior to an EMA report, mothers' negative affect subsequently increased, controlling for mean levels of infant crying. In contrast to findings from laboratory studies, in everyday settings crying exposure did not immediately increase feelings of depression. Only when crying was above average for 8 hr prior to EMA did mothers report increases in subsequent depression symptoms, suggesting that the effects of crying on maternal mental health take hours to unfold in ecologically valid home settings. Between participants, mothers of infants who cried more on average did not report higher negative affect or symptoms of depression or anxiety. Overall, our findings reveal that crying exposure dynamically influences maternal negative affect and depression but not anxiety in ecologically valid real-world settings. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The maternal brain is more flexible and responsive at rest: effective connectivity of the parental caregiving network in postpartum mothers

The field of neuroscience has largely overlooked the impact of motherhood on brain function outside the context of responses to infant stimuli. Here, we apply spectral dynamic causal modelling (spDCM) to resting-state fMRI data to investigate differences in brain function between a group of 40 first-time mothers at 1-year postpartum and 39 age- and education-matched women who have never been pregnant. Using spDCM, we investigate the directionality (top-down vs. bottom-up) and valence (inhibition vs excitation) of functional connections between six key left hemisphere brain regions implicated in motherhood: the dorsomedial prefrontal cortex, ventromedial prefrontal cortex, posterior cingulate cortex, parahippocampal gyrus, amygdala, and nucleus accumbens. We show a selective modulation of inhibitory pathways related to differences between (1) mothers and non-mothers, (2) the interactions between group and cognitive performance and (3) group and social cognition, and (4) differences related to maternal caregiving behaviour. Across analyses, we show consistent disinhibition between cognitive and affective regions suggesting more efficient, flexible, and responsive behaviour, subserving cognitive performance, social cognition, and maternal caregiving. Together our results support the interpretation of these key regions as constituting a parental caregiving network. The nucleus accumbens and the parahippocampal gyrus emerging as 'hub' regions of this network, highlighting the global importance of the affective limbic network for maternal caregiving, social cognition, and cognitive performance in the postpartum period.

Neural activation to infant cry among Latina and non-Latina White mothers

Cultural neuroscience is an emerging framework positing that culture (for example, values, beliefs, practices, and modes of emotional expression) critically informs socialization goals and desired behaviors, which are perhaps accompanied by differential patterns of brain activation. Using fMRI, the current study examines brain activation to infant cry stimuli and matched white noise among 50 first-time biological mothers identifying as Latina or White in the United States. Results showed that brain activation to infant cries in the right posterior insula, left cerebellum, and left auditory were higher for White mothers compared to Latina mothers, p's < .05. White mothers showed greater activation to cry sounds compared to white noise in the right dorsolateral prefrontal cortex, left somatosensory, right and left premotor cortices, p's < .05, whereas Latina mothers did not. These brain regions are involved in motor planning, movement, sensory processing, and social information processing. It is important to note that mothers in the two groups did not show differences in stress and behavioral parenting measures. Therefore, Latina and White mothers differentially recruiting brain regions related to infant parenting behaviors indicates the potential role of cultural context in shaping patterns of neural activation. Our exploratory analysis suggests that this difference might be due to greater pre-parenting exposure among Latina mothers to children compared to White mothers. Taken together, although our data did not completely explain the differences in brain activation between groups, findings suggest potential culture-related influences in brain activation occurring in the postpartum period.

Trait coping styles and the maternal neural and behavioral sensitivity to an infant

During the postpartum period, new mothers experience drastic changes in their body, brain, and life circumstances. Stress from the emotional and physical demands of caring for an infant is associated with negative mood and parenting outcomes. The use of active coping strategies can increase mothers’ resilience during the postpartum period. However, little is known about the association between coping styles and maternal brain responses to infant cues. In the current study, we examined the associations among trait coping style, maternal brain responses, and behavioral sensitivity in a socioeconomically diverse sample of first-time mothers (N = 59). The use of more active trait coping strategies compared to passive coping strategies was associated with increased brain responses to infant cry sounds in brain regions that are critically involved in motivation and emotion regulation—substantia nigra, anterior cingulate gyrus, and inferior frontal gyrus. Increased brain activations in the midbrain and anterior cingulate gyrus were further associated with higher levels of maternal sensitivity observed during interactions with the infant. Thus, the findings provide support for mothers’ use of more active coping styles to promote neural and behavioral resilience for a positive transition to parenthood.

Maternal socioeconomic disadvantage, neural function during volitional emotion regulation, and parenting

The transition to becoming a mother involves numerous emotional challenges, and the ability to effectively keep negative emotions in check is critical for parenting. Evidence suggests that experiencing socioeconomic disadvantage interferes with parenting adaptations and alters neural processes related to emotion regulation. The present study examined whether socioeconomic disadvantage is associated with diminished neural activation while mothers engaged in volitional (i.e., purposeful) emotion regulation. 59 mothers, at an average of 4 months postpartum, underwent fMRI scanning and completed the Emotion Regulation Task (ERT). When asked to regulate emotions using reappraisal (i.e., Reappraise condition; reframing stimuli in order to decrease negative emotion), mothers with lower income-to-needs ratio exhibited dampened neural activation in the dorsolateral and ventrolateral PFC, middle frontal and middle temporal gyrus, and caudate. Without explicit instructions to down-regulate (i.e., Maintain condition), mothers experiencing lower income also exhibited dampened response in regulatory areas, including the middle frontal and middle temporal gyrus and caudate. Blunted middle frontal gyrus activation across both Reappraise and Maintain conditions was associated with reduced maternal sensitivity during a mother-child interaction task. Results of the present study demonstrate the influence of socioeconomic disadvantage on prefrontal engagement during emotion regulation, which may have downstream consequences for maternal behaviors.

Reported maternal childhood maltreatment experiences, amygdala activation and functional connectivity to infant cry

Maternal childhood maltreatment experiences (CMEs) may influence responses to infants and affect child outcomes. We examined associations between CME and mothers' neural responses and functional connectivity to infant distress. We hypothesized that mothers with greater CME would exhibit higher amygdala reactivity and amygdala-supplementary motor area (SMA) functional connectivity to own infant's cries. Postpartum mothers (N = 57) assessed for CME completed an functional magnetic resonance imaging task with cry and white-noise stimuli. Amygdala region-of-interest and psychophysiological interaction analyses were performed. Our models tested associations of CME with activation and connectivity during task conditions (own/other and cry/noise). Exploratory analyses with parenting behaviors were performed. Mothers with higher CME exhibited higher amygdala activation to own baby's cries vs other stimuli (F1,392 = 6.9, P < 0.01, N = 57) and higher differential connectivity to cry vs noise between amygdala and SMA (F1,165 = 22.3, P < 0.001). Exploratory analyses revealed positive associations between both amygdala activation and connectivity and maternal non-intrusiveness (Ps < 0.05). Increased amygdala activation to own infant's cry and higher amygdala-SMA functional connectivity suggest motor responses to baby's distress. These findings were associated with less intrusive maternal behaviors. Follow-up studies might replicate these findings, add more granular parenting assessments and explore how cue processing leads to a motivated maternal approach in clinical populations.

Ecological Predictors of Parental Beliefs about Infant Crying in a Randomized Clinical Trial of ABC

Objective: Attachment theory suggests that parent responsiveness to infant distress predicts secure parent-child attachment and subsequent healthy child development. While much is known about microsystem factors that interfere with responsive caregiving, there is a paucity of research investigating how exosystem factors, such as neighborhood crime, affect parenting.Method: In a sample of 200 diverse caregivers and their 5- to 21-month-old infants (M = 11.82; 49% male), we leveraged data from a randomized clinical trial of Attachment and Biobehavioral Catch-up (ABC), an attachment-based intervention, to assess whether individual level burden (indicated by single-parent status, low income, residential instability, young parenthood, parental psychopathology, and own history of early adversity) and neighborhood crime density (geocoded within a 500 ft radius of parent's residence) were associated with their beliefs about infant crying, an indicator of responsive parenting.Results: Consistent with Bronfenbrenner's ecological systems' theory of development, both greater exposure to individual burden indicators and greater neighborhood crime density predicted greater maladaptive beliefs about infant crying, suggesting that contextual factors outside the household are associated with parenting cognitions. Further, when accounting for the effect of crime and individual burden on parental beliefs about infant crying, participation in the ABC intervention was effective in reducing maladaptive parenting beliefs.Conclusions: We consider implications for multi-level intervention approaches that target family processes, neighborhood-level factors, and policy initiatives to promote community wellbeing and positive child development.

How stress can influence brain adaptations to motherhood

Research shows that a woman's brain and body undergo drastic changes to support her transition to parenthood during the perinatal period. The presence of this plasticity suggests that mothers' brains may be changed by their experiences. Exposure to severe stress may disrupt adaptive changes in the maternal brain and further impact the neural circuits of stress regulation and maternal motivation. Emerging literature of human mothers provides evidence that stressful experience, whether from the past or present environment, is associated with altered responses to infant cues in brain circuits that support maternal motivation, emotion regulation, and empathy. Interventions that reduce stress levels in mothers may reverse the negative impact of stress exposure on the maternal brain. Finally, outstanding questions regarding the timing, chronicity, types, and severity of stress exposure, as well as study design to identify the causal impact of stress, and the role of race/ethnicity are discussed.