Maternal Postpartum Work Resumption Stress: Questionnaire Development and Validation.

Transitioning back to work after maternity leave is increasingly common. While differences exist, for many mothers this transition represents a stressor. This study aimed to define the construct of maternal postpartum work resumption stress and develop and validate a self-report measure in a low-risk sample of Dutch mothers. First, the item pool (N = 71) and face and content validity of the questionnaire were established. Next, two independent samples of mothers returning to work (N = 298, N = 291) were recruited to identify factor structure, reduce the number of items, and assess the dimensionality, reliability, convergent and discriminant validity of the questionnaire. Based on exploratory and confirmatory factor analyses, the reliable and valid REturn to Work INventory (REWINd) with 30 items across three factors was established. While further validation is needed, REWINd can be used to further study the nature and consequences of maternal postpartum work resumption stress.

Infant colic and HPA axis development across childhood.

This study examines the long-term impact of infant colic on Hypothalamic-Pituitary-Adrenal (HPA) axis development and the moderating role of attachment security, in a low-risk Dutch sample of 193 children. We assessed infant colic at 6 weeks, circadian cortisol concentrations at ages 1, 2.5, 6, and 10 years, and attachment security at 1 year. Findings indicated that infant colic was associated with steeper diurnal cortisol slopes and slightly higher cortisol concentrations throughout childhood. Attachment security did not moderate these associations. This is the first study to reveal a link between infant colic and the development of the HPA axis in healthy children beyond infancy. These findings have important implications for understanding early risk and protective factors in the stress system's development.

Implications of childhood adversity for women's perinatal sleep quality and depressive symptoms over time: A serial mediation model.

This study sought to examine the effects of childhood adversity on the longitudinal associations between perinatal sleep quality and depressive symptoms, and to determine the prospective associations between these constructs over time. A cross-lagged autoregressive model was used to examine the longitudinal association between sleep quality and depressive symptoms at four points during the perinatal period: 18 and 32 weeks of pregnancy, and 6 and 12 weeks postpartum. Longitudinal mediation models were used to examine whether sleep quality or depressive symptoms mediated the effects of childhood adversity on these symptoms. Most participants (86%) reported poor sleep quality during pregnancy. Significant cross-lagged effects of depressive symptoms on subsequent sleep quality were observed during pregnancy and postpartum. Depressive symptoms significantly mediated the effects of childhood trauma on sleep quality during pregnancy, but sleep quality did not significantly mediate the effects of childhood trauma on depressive symptoms. While sleep quality and depressive symptoms tend to co-occur, our analyses indicate that perinatal depressive symptoms work as the primary driver of sleep quality over time. Childhood adversity may have long-reaching effects in women as it was associated with more depressive symptoms in the perinatal period, which in turn appeared to undermine sleep quality.

Individual differences in processing speed and curiosity explain infant habituation and dishabituation performance.

Habituation and dishabituation are the most prevalent measures of infant cognitive functioning, and they have reliably been shown to predict later cognitive outcomes. Yet, the exact mechanisms underlying infant habituation and dishabituation are still unclear. To investigate them, we tested 106 8-month-old infants on a classic habituation task and a novel visual learning task. We used a hierarchical Bayesian model to identify individual differences in sustained attention, learning performance, processing speed and curiosity from the visual learning task. These factors were then related to habituation and dishabituation. We found that habituation time was related to individual differences in processing speed, while dishabituation was related to curiosity, but only for infants who did not habituate. These results offer novel insights in the mechanisms underlying habituation and serve as proof of concept for hierarchical models as an effective tool to measure individual differences in infant cognitive functioning. RESEARCH HIGHLIGHTS: We used a hierarchical Bayesian model to measure individual differences in infants' processing speed, learning performance, sustained attention, and curiosity. Faster processing speed was related to shorter habituation time. High curiosity was related to stronger dishabituation responses, but only for infants who did not habituate.

A longitudinal study of the gut microbiota during the first three years of life: Links with problem behavior and executive functions at preschool age.

Early life is a sensitive period when microbiota-gut-brain interactions may have important impact on development. This study investigated the associations of the gut microbiota in the first three years of life (two, six, and 12 weeks, and one and three years) with problem behavior and executive functions in N = 64 three-year-old children. Higher relative abundance of Streptococcus at the age of two weeks, as well as its trajectory over time (including ages two, six and 12 weeks, and one and three years), was related to worse executive functions. Higher relative abundance of [Ruminococcus] torques group at the age of three years, as well as its trajectory from one to three years, was associated with less internalizing behavior. Besides, several robust age-specific associations were identified: higher Bifidobacterium relative abundance (age three years) was associated with more internalizing and externalizing issues; higher Blautia relative abundance (age three years) was linked to less internalizing behavior; and increased relative abundance of an unidentified Enterobacteriaceae genus (age two weeks) was related to more externalizing behavior. Our findings provide important longitudinal evidence that early-life gut microbiota may be linked to behavioral and cognitive development in low-risk children.

Are adolescent diet quality and emotional eating predicted by history of maternal caregiving quality and concurrent inhibitory control?

The risk for unhealthy eating behaviour, including poor diet quality and emotional eating, is heightened in adolescence and could result in profound and long-lasting psychological and physical implications. Caregiving quality and adolescents' regulatory skills, such as inhibitory control, may play an essential role in the development of adolescent eating behaviour. This preregistered study investigated whether maternal caregiving throughout the first 14 years of life predicts adolescent diet quality and emotional eating and whether potential associations are mediated by adolescents' inhibitory control. In this low-risk community cohort, maternal caregiving quality was observed at child ages five weeks, 12 months, 2.5, 10, and 14 years. At age 14, diet quality and emotional eating were assessed through self-report. Adolescent inhibitory control was assessed with three behavioural tasks and a maternal report. Mediation analyses were performed with structural equation modelling in R. No evidence was found for links between maternal caregiving quality and adolescent diet quality and emotional eating. Higher levels of adolescent inhibitory control predicted better adolescent diet quality. Longitudinal and experimental studies are needed to investigate directionality, and replication studies are needed in more representative samples (e.g. including high-risk families). Such studies will shed further light on potential links between the history of caregiving behaviour and adolescent regulatory and eating behaviour.

Breastfeeding and room-sharing during COVID-19 in the Netherlands: The impact of perinatal healthcare support.

AIM: The recommendations of 6 months of exclusive breastfeeding (EBF) and parent-infant room-sharing (RS) are often not followed. As these early caregiving practices may have been affected by the COVID-19-related restrictions, we documented BF and RS practices in the Netherlands (2020-2021) and the effects of perceived perinatal healthcare support. METHODS: Pregnant women and mothers of an infant younger than 6 months (N = 784) completed online questionnaires (e.g., demographic information, the impact of COVID-19 on their lives aspects, infant childcare practices) twice: at the beginning of the pandemic and when the infant reached 6 months of age. RESULTS: The pandemic EBF practices mirrored pre-pandemic Dutch reports (17.8 %; Mduration = 3.4 months), while RS rates and duration seemingly doubled (30.6 %; Mduration = 3.98 months). Higher maternal education (r = 0.18) and multiparity (r = 0.08) were significantly associated with longer EBF, and similarly for education (r = 0.17) and multiparity (r = 0.11) with RS durations. Higher perceived perinatal healthcare support predicted shorter RS duration [ß = -0.509, t(5,596) = -2.27, p = .023]. CONCLUSION: While the COVID-19 pandemic did not impact EBF, it may have promoted RS. The negative association between perinatal healthcare support and RS may suggest that parents who need more support from their providers also experience more challenges adhering to RS recommendations, yet this hypothesis remains to be corroborated.

Maternal sensitivity and child internalizing and externalizing behavior: a mediating role for glucocorticoid receptor gene (NR3C1) methylation?

The early caregiving environment can have lasting effects on child mental health. Animal models suggest that glucocorticoid receptor gene (NR3C1) DNA methylation plays a mediating role in linking more responsive caregiving to improved behavioral outcomes by its impact on the stress regulatory system. In this longitudinal study, we examined whether children's NR3C1 methylation levels mediate an effect of maternal sensitivity in infancy on levels of child internalizing and externalizing behavior in a community sample. Maternal sensitivity of 145 mothers was rated at infant age 5 weeks, 12 months, and 30 months by observing mother-infant interactions. Buccal DNA methylation was assessed in the same children at age 6 years and maternal-reported internalizing and externalizing behavior was assessed at age 6 and 10 years. Higher sensitivity at age 5 weeks significantly predicted lower DNA methylation levels at two NR3C1 CpG loci, although methylation levels at these loci did not mediate an effect of maternal sensitivity on levels of child internalizing and externalizing behavior. Overall, the study provides evidence that maternal sensitivity in early infancy is associated with DNA methylation levels at loci involved in stress regulation, but the significance of this finding for child mental health remains unclear.

Fucosylated Human Milk Oligosaccharides during the First 12 Postnatal Weeks Are Associated with Better Executive Functions in Toddlers.

Human milk oligosaccharides (HMOs) are one of the most abundant solid components in a mother's milk. Animal studies have confirmed a link between early life exposure to HMOs and better cognitive outcomes in the offspring. Human studies on HMOs and associations with later child cognition are scarce. In this preregistered longitudinal study, we investigated whether human milk 2'-fucosyllactose, 3'-sialyllactose, 6'-sialyllactose, grouped fucosylated HMOs, and grouped sialylated HMOs, assessed during the first twelve postnatal weeks, are associated with better child executive functions at age three years. At infant age two, six, and twelve weeks, a sample of human milk was collected by mothers who were exclusively (n = 45) or partially breastfeeding (n = 18). HMO composition was analysed by use of porous graphitized carbon-ultra high-performance liquid chromatography-mass spectrometry. Executive functions were assessed at age three years with two executive function questionnaires independently filled in by mothers and their partners, and four behavioural tasks. Multiple regression analyses were performed in R. Results indicated that concentrations of 2'-fucosyllactose and grouped fucosylated HMOs were associated with better executive functions, while concentrations of grouped sialylated HMOs were associated with worse executive functions at age three years. Future studies on HMOs that sample frequently during the first months of life and experimental HMO administration studies in exclusively formula-fed infants can further reveal associations with child cognitive development and uncover potential causality and sensitive periods.

Maternal anxiety forecasts shorter prolongation of pregnancies complicated by early-onset preeclampsia.

PURPOSE: In early-onset preeclampsia, each additional day of pregnancy prolongation reduces offspring infant mortality about 9%. We evaluated if maternal stress at admission to hospital for early-onset preeclampsia predicted admission-to-delivery intervals in days. METHODS: This prospective, longitudinal cohort-study involved 15 singleton pregnancies with a diagnosis of preeclampsia before 34 weeks gestation with intended expectant management. Upon hospital admission, maternal psychological stress was assessed with questionnaires and physiological stress with hair cortisol. Hair samples were analyzed in three hair segments representing the preconception period, and the first and second trimester of pregnancy. RESULTS: Mean pregnancy prolongation was 16.2 days. Higher maternal anxiety at hospital admission significantly correlated with shorter admission-to-delivery intervals (r = - 0.54, p = 0.04). Chronically increased hair cortisol concentrations (i.e. from preconception through the second trimester) of pregnancy tended to be related to shorter admission-to-delivery intervals (p <. 10). CONCLUSION: Higher reported anxiety is, and chronically high hair cortisol tended to be, related with fewer days of prolongation from admission to delivery in women with early-onset preeclampsia. These findings suggest that maternal stress might be a potential determinant of disease progression. Future research into early innovative stress-reducing interventions for early-onset preeclampsia may shed more light on the etiology and treatment of this disease.

Cumulative risk exposure and child cellular aging in a Dutch low-risk community sample.

One of the proposed mechanisms linking childhood stressor exposure to negative mental and physical health outcomes in later life is cellular aging. In this prospective, longitudinal, and pre-registered study, we examined the association between a cumulative pattern of childhood risk exposure from age 6 to age 10 (i.e., poor maternal mental health, parental relationship problems, family/friend death, bullying victimization, poor quality friendships) and change in two biomarkers of cellular aging (i.e., telomere length, epigenetic age) from age 6 to age 10 in a Dutch low-risk community sample (n = 193). We further examined the moderating effect of cortisol reactivity at age 6. Ordinary Least Squares regression analyses revealed no significant main effects of childhood risk exposure on change in cellular aging, nor a moderation effect of child cortisol reactivity. Secondary findings showed a positive correlation between telomere length and cortisol reactivity at age 6, warranting further investigation. More research in similar communities is needed before drawing strong conclusions based on the null results.

Effects of daily full-term infant skin-to-skin contact on behavior and cognition at age three - secondary outcomes of a randomized controlled trial.

BACKGROUND: Daily skin-to-skin contact (SSC) during early infancy fosters the long-term development of children born preterm. This is the first randomized controlled trial assessing the potential beneficial effects of daily SSC on executive functioning and socio-emotional behavior of children born full-term. Whether children of mothers who experienced prenatal stress and anxiety benefitted more from SSC was also explored. METHODS: Pregnant women (N = 116) were randomly assigned to a SSC or care-as-usual (CAU) condition. Women in the SSC condition were instructed to perform one hour of SSC daily from birth until postnatal week five. Prenatal stress was measured with questionnaires on general and pregnancy-specific stress and anxiety completed by the mothers in gestational week 37. At child age three, mothers filled in questionnaires on children's executive functioning, and externalizing and internalizing behavior. Analyses were performed in an intention-to-treat (ITT), per-protocol, and dose-response approach. Netherlands Trial Register: NL5591. RESULTS: In the ITT approach, fewer internalizing (95% CI = 0.11-1.00, U = 2148.50, r = .24, p = .001) and externalizing (95% CI = 0.04-2.62, t = 2.04, d = 0.38, p = .04) problems were reported in the SSC condition compared to the CAU condition. Multivariate analyses of variance did not show group differences on executive functioning. Additional analyses of covariance showed no moderations by maternal prenatal stress. CONCLUSIONS: Current findings indicate that early daily SSC in full-term infants may foster children's behavioral development. Future replications, including behavioral observations of child behavior to complement maternal reports, are warranted.

Human milk: From complex tailored nutrition to bioactive impact on child cognition and behavior.

Human milk is a highly complex liquid food tailor-made to match an infant's needs. Beyond documented positive effects of breastfeeding on infant and maternal health, there is increasing evidence that milk constituents also impact child neurodevelopment. Non-nutrient milk bioactives would contribute to the (long-term) development of child cognition and behavior, a process termed 'Lactocrine Programming'. In this review we discuss the current state of the field on human milk composition and its links with child cognitive and behavioral development. To promote state-of-the-art methodologies and designs that facilitate data pooling and meta-analytic endeavors, we present detailed recommendations and best practices for future studies. Finally, we determine important scientific gaps that need to be filled to advance the field, and discuss innovative directions for future research. Unveiling the mechanisms underlying the links between human milk and child cognition and behavior will deepen our understanding of the broad functions of this complex liquid food, as well as provide necessary information for designing future interventions.

Relations between bedtime parenting behaviors and temperament across 14 cultures.

Objectives: The present study examined parental sleep-supporting practices during toddlerhood in relation to temperament across 14 cultures. We hypothesized that passive sleep-supporting techniques (e.g., talking, cuddling), but not active techniques (e.g., walking, doing an activity together), would be associated with less challenging temperament profiles: higher Surgency (SUR) and Effortful Control (EC) and lower Negative Emotionality (NE), with fine-grained dimensions exhibiting relationships consistent with their overarching factors (e.g., parallel passive sleep-supporting approach effects for dimensions of NE). Methods: Caregivers (N = 841) across 14 cultures (M = 61 families per site) reported toddler (between 17 and 40 months of age; 52% male) temperament and sleep-supporting activities. Utilizing linear multilevel regression models and group-mean centering procedures, we assessed the role of between- and within-cultural variance in sleep-supporting practices in relation to temperament. Results: Both within-and between-culture differences in passive sleep-supporting techniques were associated with temperament attributes, (e.g., lower NE at the between-culture level; higher within-culture EC). For active techniques only within-culture effects were significant (e.g., demonstrating a positive association with NE). Adding sleep-supporting behaviors to the regression models accounted for significantly more between-culture temperament variance than child age and gender alone. Conclusion: Hypotheses were largely supported. Findings suggest parental sleep practices could be potential targets for interventions to mitigate risk posed by challenging temperament profiles (e.g., reducing active techniques that are associated with greater distress proneness and NE).

Effects of skin-to-skin contact on full-term infants' stress reactivity and quality of mother-infant interactions.

Skin-to-skin contact (SSC) between mothers and their infants has beneficial effects in both preterm and full-term infants. Underlying mechanisms are largely unknown. This randomized controlled trial assessed whether daily SSC in full-term mother-infant dyads: (1) decreases infants' cortisol and behavioral reactivity to a mild naturalistic stressor, and (2) facilitates interaction quality between infants and mothers (i.e., improved maternal caregiving behavior and mother-infant adrenocortical synchrony). Pregnant Dutch women (N = 116) were recruited and randomly allocated to an SSC or care-as-usual condition. The SSC condition performed 1 h of SSC daily, from birth until postnatal week 5. In week 5, mothers bathed the infant (known mild stressor). Infant and maternal cortisol was sampled at baseline, 25 and 40 min after bathing, and infant and maternal behavior was rated. Results did not indicate effects of SSC on infant behavioral and cortisol reactivity to the bathing session. Similarly, no effect of SSC was found on maternal caregiving behavior and mother-infant adrenocortical synchrony. In conclusion, the findings provide no evidence that daily mother-infant SSC is associated with full-term infants' behavioral and adrenocortical stress reactivity or mother-infant interaction quality. Future studies should replicate these findings and unveil other potential mechanisms underlying beneficial effects of SSC.

Attachment insecurity and the biological embedding of reproductive strategies: Investigating the role of cellular aging.

Evolutionary-developmental psychologists have posited that individuals who grow up in stressful rearing circumstances follow faster life history strategies, thereby increasing their chances of reproduction. This preregistered study tested this stress-acceleration hypothesis in a low-risk longitudinal sample of 193 Dutch mother-child dyads, by investigating whether infant-mother attachment insecurity at 12 months of age predicted earlier pubertal onset and more callous-unemotional traits, aggression and risk-taking about a decade later. Also evaluated were the possible mediating roles of two biomarkers of accelerated aging (i.e., telomere length, epigenetic aging) at age 6. Structural equation modelling revealed no effects of attachment insecurity on biomarkers, pubertal timing or behavior. These null findings suggest that the explanatory value of evolutionary-developmental thinking might be restricted to high-risk samples, though unexplored variation in susceptibility to environmental influences might also explain the null findings.

No evidence for association between late pregnancy maternal cortisol and gray matter volume in a healthy community sample of young adolescents.

A compelling amount of animal and human research has shown that perceived maternal stress during pregnancy can affect the neurodevelopment of the offspring. Prenatal maternal cortisol is frequently proposed as the biological key mechanism underlying this link; however, literature that investigates the effects of prenatal cortisol on subsequent neurodevelopment in humans is scarce. By using longitudinal data from a relatively large community sample of mother-child dyads (N = 73), this pre-registered study prospectively examined the role of maternal prenatal cortisol concentrations on subsequent individual differences in gray matter volume (GMV) and hippocampal subfield volumes at the onset of puberty of the offspring (12 years of age). Two markers of cortisol, that is, evening cortisol and circadian decline over the day, were used as indicators of maternal physiological stress during the last trimester of pregnancy. The results indicate that prenatal maternal cortisol levels were not associated with GMV or hippocampal subfield volumes of the children. These findings suggest that late pregnancy maternal cortisol may not be related to the structural development of the offspring's brain, at least not in healthy community samples and at the onset of puberty. When examining the influence of prenatal stress on offspring neurodevelopment, future investigations should delineate gestational timing effects of the cortisol exposure, cortisol assessment method, and impact of additional biomarkers, as these were not investigated in this study.

Prenatal hair cortisol concentrations during the COVID-19 outbreak: Associations with maternal psychological stress and infant temperament.

BACKGROUND: Maternal psychological stress during pregnancy, including stress resulting from disasters and trauma, has been linked to temperamental difficulties in offspring. Although heightened cortisol concentrations are often hypothesized as an underlying mechanism, evidence supporting this mechanism is not consistent, potentially because of methodological issues and low stress in the population. AIM: To address these issues, this preregistered study investigated the following associations between: 1) prenatal psychological stress and hair cortisol, as a biomarker for chronic stress, during the COVID-19 outbreak (i.e., as a major worldwide psychological stressor), and 2) maternal hair cortisol during the COVID-19 outbreak and later infant temperamental negative affectivity and orienting/regulation. Additionally, we explored whether associations were different for women with low versus high socioeconomic status (SES; maternal education and annual household income) and at different stages of pregnancy. METHOD: Pregnant women (N = 100) filled out online questionnaires during the first COVID-19 lockdown. Six months later, when most mothers were still pregnant or had just given birth, maternal hair samples were collected during home visits. When infants were six months old, mothers reported on their infant's temperament. RESULTS: Although hierarchical regression analyses revealed no associations between prenatal COVID-19 psychological stress and hair cortisol during the COVID-19 outbreak, SES proved to be a moderator in this association. Only pregnant women with higher levels of SES, not lower levels, showed a positive association between work-related and social support-related COVID-19 worries and hair cortisol. Finally, prenatal hair cortisol was not associated with later infant temperamental negative affectivity and orienting/regulation. CONCLUSION: Although the COVID-19 outbreak proved to be a major psychological stressor worldwide, the physiological impact of the crisis might be different for pregnant women with higher SES as compared to lower SES.

Daily skin-to-skin contact and crying and sleeping in healthy full-term infants: A randomized controlled trial.

This randomized controlled trial (NTR5697) examined the effects of a 5-week daily skin-to-skin contact (SSC) intervention, compared with care-as-usual, on full-term infant crying and sleeping duration during the first 12 weeks postnatally (secondary outcomes of this trial). This trial included 116 Dutch healthy mothers and their full-term infants. SSC mothers were instructed to provide 1 hr daily of SSC for the first 5 weeks postpartum. Intention-to-treat analyses revealed no group differences in infant crying (i.e., total duration and mean bout length) and sleeping (i.e., total duration and mean bout length). Per-protocol analyses, including only the SSC dyads who adhered to SSC guidelines, indicated that SSC reduced infant total crying duration and the crying bout length. Similarly, dose-response analyses indicated that more SSC minutes were associated with less infant crying (i.e., shorter total duration and bout length) and longer total sleeping duration, especially when the infant was younger. No group differences and associations were found with sleeping bout length. Mother-infant SSC, when performed regularly, may be a cost-effective intervention to reduce infant crying and potentially also extend infant sleep duration. (PsycInfo Database Record (c) 2022 APA, all rights reserved).