Developmental foundations of physiological dynamics among mother-infant dyads: The role of newborn neurobehavior

Examining the implications of contextual stress and maternal sensitivity for infants' cortisol responses to the still face paradigm

Infants' hypothalamic-pituitary-adrenocortical (HPA) axis responses to acute stressors are theorized to be shaped by parents' sensitive responsiveness to infants' cues. The strength and direction of the association between maternal sensitivity and infants' HPA responses may depend on the context in which maternal sensitivity is observed and on broader environmental sources of stress and support. In this preregistered study, we used data from 105 mothers and their 7-month-old infants to examine whether two empirically identified forms of contextual stress-poor maternal psychosocial wellbeing and family socioeconomic hardship-moderate the association between maternal sensitivity and infants' cortisol responses to the Still-Face Paradigm (SFP). Results indicated that maternal sensitivity during the free play and family socioeconomic hardship interacted to predict infants' cortisol responses to the SFP. Specifically, maternal sensitivity during this non-distressing interaction was negatively associated with cortisol responses only among infants whose mothers were experiencing relatively high socioeconomic hardship. Exploratory analyses revealed that poor maternal psychosocial wellbeing was positively associated with overall infant cortisol production during the SFP. Altogether, these findings suggest that experiences within early parent-infant attachment relationships and sources of contextual stress work together to shape infant HPA axis activity.

Grandmother-grandchild physiological synchrony in Chinese three-generation families: Links with child emotion regulation

The current study examined the characteristics of physiological synchrony between grandmothers and grandchildren in Chinese three-generation families, and the associations between physiological synchrony and child emotion regulation. The participants included 92 children (age 8-10-year old) and their grandmothers. Respiratory sinus arrhythmia (RSA) was collected from both grandmothers and their grandchildren throughout a collaborative drawing task and a conflict discussion task. Child emotion regulation was measured using the Children's Emotional Management Scale. We found no evidence for an overall pattern of concordant or discordant synchrony within dyads. Instead, there was great variability in patterns of synchrony across dyads. During the collaborative drawing task, concordance in grandmother's RSA and grandchildren's subsequent RSA was linked with better emotion regulation. During the conflict discussion, concordance in grandmother's RSA and grandchildren's simultaneous RSA was linked with poorer emotion regulation. These results suggest that grandmother-grandchild synchrony in different directions, time lags, and contexts has different influences on children's emotion regulation. The findings of this study highlight the importance of contextual physiological co-regulation between Chinese children and their grandmothers for children's social-emotional development.

Evidence for neurobehavioral risk phenotypes at birth

Observations of newborn behavior provide clinicians and researchers with a first description of the neurobehavioral organization of the newborn that is largely independent of the postnatal environment. The Neonatal Network Neurobehavioral Scale (NNNS) was developed in 2004 to evaluate how prenatal exposure to substances such as cocaine is related to neurobehavioral outcomes. There are now 156 empirical articles published using the NNNS, which we review and summarize. Z-scores from published studies using the NNNS were compiled and aggregated supporting the replicability of three newborn neurobehavioral phenotypes: one typical and two that are predictive of later cognitive and behavioral delay; hyper- and hypo-dysregulated newborns. These phenotypes emerged from independent samples and research groups and were identified in a variety of populations, including infants with prenatal substance exposure, preterm infants, and healthy term infants. Our findings show that newborn neurobehavior can be measured in a reliable and valid manner and that certain behavioral phenotypes, identifiable at birth, can predict neurodevelopmental challenges. These findings have important clinical utility. Intervening early with infants exhibiting these risk phenotypes may prevent later neurodevelopmental delay. IMPACT: We reviewed all empirical studies published using the Neonatal Network Neurobehavioral Scale and found evidence for two replicable stress phenotypes that predict later behavioral outcomes. This study highlights the utility of the Neonatal Network Neurobehavioral Scale for early identification of newborn neurodevelopmental risk phenotypes. Early identification of neurodevelopmental risk, when neuroplasticity is high, may ultimately reduce the burden of subsequent neurobehavioral problems through early intervention.

Pregnant women's autonomic responses to an infant cry predict young infants' behavioral avoidance during the still-face paradigm

Research suggests that women's autonomic nervous system responses to infant cries capture processes that affect their parenting behaviors. The aim of this study was to build on prior work by testing whether pregnant women's autonomic responses to an unfamiliar infant crying also predict their infants' emerging regulation abilities. Participants included 97 women in their third trimester of pregnancy, located in the United States. Most participants identified as White/non-Hispanic (48%) or Hispanic (30%), their mean age was approximately 30 years, and the modal family income was $40,000-$79,999. Pregnant women's respiratory sinus arrhythmia (RSA) and skin conductance levels (SCL)-which are thought to capture emotional engagement and behavioral inhibition, respectively-were measured while the women watched a relaxing video and a video of an unfamiliar infant crying. Approximately 7 months later, women and their infants completed the still-face paradigm (SFP). Infants' avoidance and resistance behaviors during the SFP reunions were rated. Pregnant women's RSA and SCL responses to the infant cry video uniquely predicted infants' avoidance (but not resistance) during the SFP. Infants displayed higher levels of avoidance when their mothers exhibited lower levels of RSA reactivity or when their mothers exhibited higher levels of SCL activity in response to the infant cry video. Maternal sensitivity during mother-infant free-play interactions did not mediate the associations between pregnant women's autonomic responses to the cry video and infants' avoidant behavior during the SFP. Discussion focuses on potential mechanisms underlying associations between pregnant women's autonomic responses to infant distress and infants' socioemotional development. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Parents' Physiological Reactivity to Child Distress and Associations with Parenting Behaviour: A Systematic Review

This systematic review and narrative synthesis characterized parents' physiological stress responses to child distress and how parents' physiological and behavioural responses relate. The review was pre-registered with PROSPERO (#CRD42021252852). In total, 3,607 unique records were identified through Medline, Embase, PsycINFO, and CINAHL. Fifty-five studies reported on parents' physiological stress responses during their young child's (0-3 years) distress and were included in the review. Results were synthesized based on the biological outcome and distress context used and risk of bias was evaluated. Most studies examined cortisol or heart rate variability (HRV). Small to moderate decreases in parents' cortisol levels from baseline to post-stressor were reported across studies. Studies of salivary alpha amylase, electrodermal activity, HRV, and other cardiac outcomes reflected weak or inconsistent physiological responses or a paucity of relevant studies. Among the studies that examined associations between parents' physiological and behavioural responses, stronger associations emerged for insensitive parenting behaviours and during dyadic frustration tasks. Risk of bias was a significant limitation across studies and recommendations for future research are discussed.

Annual Research Review: Prenatal opioid exposure - a two-generation approach to conceptualizing neurodevelopmental outcomes

Opioid use during pregnancy impacts the health and well-being of two generations: the pregnant person and the child. The factors that increase risk for opioid use in the adult, as well as those that perpetuate risk for the caregiver and child, oftentimes replicate across generations and may be more likely to affect child neurodevelopment than the opioid exposure itself. In this article, we review the prenatal opioid exposure literature with the perspective that this is not a singular event but an intergenerational cascade of events. We highlight several mechanisms of transmission across generations: biological factors, including genetics and epigenetics and the gut-brain axis; parent-child mechanisms, such as prepregnancy experience of child maltreatment, quality of parenting, infant behaviors, neonatal opioid withdrawal diagnosis, and broader environmental contributors including poverty, violence exposure, stigma, and Child Protective Services involvement. We conclude by describing ways in which intergenerational transmission can be disrupted by early intervention.

Breastfeeding duration and vagal regulation of infants and mothers

BACKGROUND

Vagal regulation within the parasympathetic nervous system supports self-regulation and social engagement. Research has suggested that early feeding practices may influence mother-infant vagal functioning.

AIM

We aimed to examine the association between breastfeeding duration and mother-infant vagal regulation during an interaction. We hypothesized that breastfeeding duration would be positively associated with adaptive vagal regulation in infants and mothers.

METHOD

204 mother-infant dyads (infant mean age 6 months) completed the face-to-face still-face (FFSF) task. During the task, vagal regulation indexed by respiratory sinus arrhythmia (RSA, a component of heart rate variability) was calculated through continuously recorded electrocardiogram signals. Breastfeeding duration and demographic information were reported by mothers. Linear mixed models were adopted to estimate the associations between breastfeeding duration and repeated measures of RSA in infants and mothers throughout the FFSF.

RESULTS

Infants breastfed for a longer duration demonstrated lower RSA throughout the FFSF (B = -0.06, 95 % CI: -0.09 to -0.03), suggesting active physiological mobilization to engage in interaction and regulate distress. Mothers with longer breastfeeding duration displayed higher baseline RSA and higher overall RSA levels (higher vagal control) during the FFSF (B = 0.06, 95 % CI: 0.02 to 0.09), indicating a calmer and regulated state.

CONCLUSION

Longer breastfeeding duration was associated with more adaptive mother-infant vagal regulation during the interaction, indicating a positive dose-response association. This finding reveals breastfeeding practice as a factor contributing to infant effective vagal regulation and further supports WHO recommendation on exclusive breastfeeding for the first 6 months and continuing breastfeeding to 24 months and beyond.

A systematic review and meta-analysis of the association between parenting and child autonomic nervous system activity

Parental socialization may influence the development of children's autonomic nervous system (ANS), a key stress-response system. However, to date no quantitative synthesis of the literature linking parenting and child ANS physiology has been conducted. To address this gap, we conducted a pre-registered meta-analysis. A systematic review of the literature identified 103 studies (n = 13,044 participants) with available effect sizes describing the association between parenting and either parasympathetic nervous system (PNS) or sympathetic nervous system (SNS) activity in children. The overall analysis revealed non-significant associations between parenting and child ANS physiology on average. However, moderation analyses revealed a positive association between more positive parenting and higher resting PNS activity that was stronger when a study was experimental rather than correlational, and when the sample included children with a clinical condition. In conclusion, well-controlled experimental studies show that positive parenting is associated with the development of higher resting PNS activity, an effect that may be stronger among children who are at elevated developmental risk.