Prenatal and Intrapartum Factors Associated With Infant Temperament: A Systematic Review

Individual and joint effects of prenatal PM2.5 and maternal stress on child temperament

Prenatal fine particulate matter (PM2.5) and maternal psychological functioning have been associated with child cognitive outcomes, though their independent and joint impacts on earlier behavioral outcomes remains less studied. We used data from 382 mother-child pairs from a prospective birth cohort in Mexico City. Temperament was measured at 24 months using the Carey Toddler Temperament Scale (TTS). Exploratory factor analysis (EFA) was used to update the factor structure of the TTS. During pregnancy, mothers completed the Crisis in Family Systems-Revised, Edinburgh Depression Scale, pregnancy-specific anxiety scale, and the Perceived Stress Scale. Pregnancy PM2.5 was assessed using estimates from a satellite-based exposure model. We assessed the association between prenatal maternal stress and PM2.5 on temperament, in both independent and joint models. Quantile g-computation was used to estimate the joint associations. Models were adjusted for maternal age, SES, education, child sex, and child age. In EFA, we identified three temperament factors related to effortful control, extraversion, and negative affect. Our main results showed that higher levels of PM2.5 and several of the maternal psychological functioning measures were related to both effortful control and negative affect in the child, both individually and as a mixture. For instance, a one quartile increase in the prenatal mixture was associated with higher negative affect scores in the child (0.34, 95% CI: 0.16, 0.53). We observed modification of these associations by maternal SES, with associations seen only among lower SES participants for both effortful control (-0.45, 95% CI: -0.70, -0.20) and negative affect outcomes (0.60, 95% CI: 0.35, 0.85). Prenatal PM2.5 and maternal psychological functioning measures were associated with toddler temperament outcomes, providing evidence for impacts of chemical and non-chemical stressors on early child health.

Does early child negative emotionality moderate the association between maternal stimulation and academic readiness and achievement?

We investigated whether child temperament (negative emotionality, 5 months) moderated the association between maternal stimulation (5 months-2½ years) and academic readiness and achievement (vocabulary, mathematics, and reading). We applied structural equation modeling to the data from the Quebec Longitudinal Study of Child Development (N = 1121-1448; mostly Whites; 47% girls). Compared to children with low negative emotionality, those with high negative emotionality had higher levels of academic readiness (6 years) and mathematics achievement (7 years) when exposed to high levels of maternal stimulation (β = 3.17, p < .01 and β = 2.91, p < .01, respectively). The results support the differential susceptibility model whereby highly emotionally negative children were more susceptible to the influences of low and high levels of maternal stimulation in academic readiness and mathematics achievement's developments.

A longitudinal study examining the associations between prenatal and postnatal maternal distress and toddler socioemotional developmental during the COVID-19 pandemic

Elevated psychological distress, experienced by pregnant women and parents, has been well-documented during the COVID-19 pandemic. Most research focuses on the first 6-months postpartum, with single or limited repeated measures of perinatal distress. The present longitudinal study examined how perinatal distress, experienced over nearly 2 years of the COVID-19 pandemic, impacted toddler socioemotional development. A sample of 304 participants participated during pregnancy, 6-weeks, 6-months, and 15-months postpartum. Mothers reported their depressive, anxiety, and stress symptoms, at each timepoint. Mother-reported toddler socioemotional functioning (using the Brief Infant-Toddler Social and Emotional Assessment) was measured at 15-months. Results of structural equation mediation models indicated that (1) higher prenatal distress was associated with elevated postpartum distress, from 6-weeks to 15-months postpartum; (2) associations between prenatal distress and toddler socioemotional problems became nonsignificant after accounting for postpartum distress; and (3) higher prenatal distress was indirectly associated with greater socioemotional problems, and specifically elevated externalizing problems, through higher maternal distress at 6 weeks and 15 months postpartum. Findings suggest that the continued experience of distress during the postpartum period plays an important role in child socioemotional development during the COVID-19 pandemic.

The Role of the Pediatrician in the Promotion of Healthy, Active Living

Few children and adolescents meet federal nutrition or physical activity recommendations, and many experience poor or inadequate sleep and negative health effects from screen use and social media. These lifestyle factors exacerbate physical and mental health risks for children and adolescents. This clinical report provides guidance to help pediatricians address the nutritional, physical activity, sleep, media and screen use, and social-emotional factors that affect child and adolescent health and wellness. The recommendations in this clinical report aim to promote health and wellness practices for infants, children, and adolescents across several domains of influence, including the individual, interpersonal, institutional, community, and public policy levels.

Associations between a metal mixture and infant negative affectivity: Effect modification by prenatal cortisol and infant sex

In-utero exposures interact in complex ways that influence neurodevelopment. Animal research demonstrates that fetal sex moderates the impact of joint exposure to metals and prenatal stress measures, including cortisol, on offspring socioemotional outcomes. Further research is needed in humans. We evaluated the joint association of prenatal exposures to a metal mixture and cortisol with infant negative affectivity, considering sex differences. Analyses included 226 (29% White, Non-Hispanic) mother-infant pairs with data on exposures and negative affectivity assessed using the Infant Behavior Questionnaire-Revised in 6-month-olds. Results showed that girls whose mothers had higher cortisol had significantly higher scores of Fear and Sadness with greater exposure to the mixture. Examining higher-order interactions may better elucidate the effects of prenatal exposure to metals and cortisol on socioemotional functioning.

Prenatal iron supplementation adjusted to maternal iron stores reduces behavioural problems in 4-year-old children

Prenatal iron supplementation improves children's health and cognitive performance, but few studies explore behavioural development. This study assessed the effects of adjusting prenatal iron supplementation to maternal iron stores during early pregnancy on children's behavioural problems. Randomized controlled trial conducted in Tarragona (Spain) involving 230 nonanaemic pregnant women and their children after a 4-year follow-up. Based on haemoglobin (Hb) levels before gestational week (GW) 12, women receive different iron doses: those with Hb = 110-130 g/L were randomized to receive 80 or 40 mg/day and those with Hb > 130 g/L were randomized to receive 20 or 40 mg/day. Maternal iron stores at GW12 were classified using serum ferritin (SF) as low (SF < 15 µg/L), normal (SF = 15-65 µg/L), and normal-high (SF > 65 µg/L). Children's behaviour was assessed by parents using the Child Behaviour Checklist for ages 1.5-5 years and the Behaviour Rating Inventory of Executive Function-Preschool Version, and by teachers using the Teacher's Report Form for ages 1.5-5 years. Multivariable regression models were performed. Taking 80 mg/day of iron improved child behaviour when women had low iron stores but worsened it when mothers had normal-high iron stores, except for depressive and attention/hyperactivity problems. Taking 20 mg/day of iron improved behaviour only in those children whose mothers had SF > 65 µg/L in early pregnancy. Additionally, executive functioning improved at high doses of prenatal iron when maternal baseline SF < 15 µg/L. Adjusting prenatal iron supplementation to both maternal baseline Hb levels and iron stores reduces behavioural problems in 4-year-old children.

Prenatal anxiety during the pandemic context is related to neurodevelopment of 6-month-old babies

Prenatal anxiety and depression in pandemic context could introduce changes in the fetal developmental trajectories that, ultimately, could alter the adaptive behaviors of the offspring, potentially affecting, for example, general neurodevelopment. The sample consisted of 105 mother-child dyads, recruited between March and May 2020. The dyads were evaluated longitudinally, prenatally and postnatally (6 months). The Pandemic Impact Questionnaire, the State-Trait Anxiety Inventory, and the Beck-II Depression Inventory were used to assess indicators of maternal anxiety and depression, respectively. Regarding the babies, their mothers responded to Age and Stages: 3, which assesses different dimensions of early neurodevelopment, in addition to a closed questionnaire to identify sociodemographic and maternal and child health variables. A series of mediation models were tested to examine the association between prenatal psychopathology/negative experiences of the pandemic and neurodevelopment. The results indicated that the negative experiences of the pandemic were indirectly associated with the socio-individual and fine motor neurodevelopment of the offspring, through maternal anxiety symptoms, during the third trimester, which functioned as a mediator.  Conclusions: This study provides evidence on the mediating effects of maternal anxiety on infant neurodevelopment in contexts of early adversity. It is important to point out the need to implement public health policies that allow a timely evaluation of neurodevelopmental variables during early childhood, which can implement early interventions to reduce the risks associated with these deficits. What is Known: • Effects of maternal mental health have been reported, effects on child neurodevelopment, in motor, cognitive, linguistic and socio-emotional dimensions. • Contexts of early adversity have been associated with maternal mental health and offspring development. What is New: • The context of pandemic adversity caused by COVID-19 is associated with motor and socio-individual neurodevelopment, mediated by maternal prenatal anxiety.

Maternal anxiety, exposure to the COVID-19 pandemic and socioemotional development of offspring

The COVID-19 pandemic context may predispose mothers to increased maternal psychopathology, which may be associated with offspring socioemotional development. The aim of this study is to analyze the relationships between prenatal anxiety and depression and exposure to the COVID-19 pandemic with offspring socioemotional development, controlling for postnatal anxiety and depression. A total of 105 mother-child dyads were assessed in pre- and postnatal periods. Questionnaires were used to assess the impact of the pandemic, indicators of psychopathology, and the socioemotional development of the offspring. Results suggest that negative pandemic experiences are indirectly associated with offspring socioemotional development via prenatal maternal anxiety symptomatology and after controlling for postnatal anxiety and depression. These indicators predispose to emotional deficits and increase the risks of psychopathological and neurodevelopmental disorders. It is important to adopt health policies that provide timely assessment of development in early childhood to reduce the risks associated with these deficits.

Maternal psychological functioning mediates the association between infant behavior and subsequent child psychological functioning

Symptoms of psychopathology that onset during childhood are often more severe, chronic, and difficult to treat than symptoms that first appear later in life. Maternal psychological symptoms are associated with the development of psychological symptoms in children. However, less research focuses on whether children's behaviors may presage maternal psychological difficulties that, in turn, contribute to the child's own psychological functioning. Identifying psychological difficulties in families and intervening in early life may lower risk for intergenerational transmission of subsequent psychological symptoms. Even at non-clinical or normative levels, exploring transactional models of parent-child behavior and psychological functioning may provide insight into the development of later psychological difficulties or symptoms within families. Thus, the current study examined whether difficult infant behavior (e.g., fussiness, unpredictability) is associated with future maternal psychological difficulties and subsequently, the child's own psychological functioning in early childhood. The current sample includes 847 dyads from a multi-wave birth cohort in England ('Born in Bradford'), who identified as predominantly non-White (62.2%) and socioeconomically diverse. Mothers reported on their child's behaviors at 6 months, their own psychological functioning during pregnancy and at 18 months postpartum, and their child's psychological functioning at age 3. Results of a mediation model revealed that the association between infant behavior at 6 months and child psychological functioning at 3 years is partially explained by maternal psychological functioning at 18 months, even after accounting for psychological difficulties during pregnancy, maternal age at birth, child sex, family income, and ethnicity. Post-hoc exploratory analyses revealed that the association between infant behavior, maternal psychological functioning, and subsequent child psychological functioning was significant for Pakistani British families but not White British families. These findings provide preliminary evidence that infant behaviors (e.g., temperament) may presage future maternal psychological difficulties and subsequent child psychological functioning, above and beyond previous maternal psychological functioning. Importantly, these results highlight infant behavior as a potential catalyst for later psychological difficulties within families.

Preterm infant body composition, working memory, and temperament

Altered body composition in preterm infants is associated with risks to cognitive development, but the effect specific to prefrontal cortex (PFC) development is unknown. We were interested in the impact of fat mass (FM) and fat free mass (FFM) gains out to 4 months corrected gestational age (CGA) on PFC development, as indexed by working memory and temperament. This is a prospective observational pilot study recruiting 100 preterm (<33 weeks gestation), appropriate for gestational age, and very low birth weight infants, of which 49 infants met inclusion criteria. Body composition was measured using air displacement plethysmography at hospital discharge and 4 months CGA. Questionnaire based temperament assessments were completed at 12 and 24 months CGA and a working memory assessment was completed at 24 months CGA. Associations between developmental tests and body composition obtained at term and 4 months were analyzed. Increased FM at discharge was associated with increased fear and decreased soothability at 12 months. Increased FM at 4 months was associated with increased activity level, increased distress from limitations at 12 months and decreased attentional shifting, decreased frustration, and decreased inhibitory control at 24 months. Increased FFM at 4 months was associated with increased activity level at 12 months and increased impulsivity and decreased low intensity pleasure at 24 months. In this exploratory pilot study, increased FM out to 4 months and increased FFM after discharge are associated with negative markers of infant temperament. Infant temperament may be sensitive to body composition status at least to 4 months CGA.

The Pandemial babies: effects of maternal stress on temperament of babies gestated and born during the pandemic

The COVID-19 pandemic may configure an adverse prenatal context for early development. The aim of this study was to analyze the effects of pandemic-related negative experiences, prenatal anxiety and depression on the temperament of six-month-old babies. The sample consisted of 105 mother-child dyads. A longitudinal evaluation was carried out using pre- and postnatal online surveys. Mothers completed the State-Trait Anxiety Inventory, the Beck Depression Inventory - II, the Pandemic Impact Questionnaire and the Infant Behavior Questionnaire Revised. Serial mediation models were tested, in which the pandemic-related negative experiences constituted the independent variable, the prenatal anxiety and depression were the mediators, and the children's temperament dimensions were the dependent variables. Pandemic-related negative experiences were indirectly associated with the offspring's negative affect and surgency through anxious symptomatology, which acted as a mediating variable. This was the first study to identify the effects of the COVID-19 pandemic on temperament. Such an adverse context implies risks for child development. Public health policies aiming to evaluate socioemotional variables during early childhood become necessary to allow on-time interventions for lessening these risks.

Behavioral Inhibition in the Second Year of Life Is Predicted by Prenatal Maternal Anxiety, Overprotective Parenting and Infant Temperament in Early Infancy

Background

Behavioral inhibition, characterized by shyness, fear and avoidance of novel stimuli, has been linked with internalizing personality traits in childhood, adolescence and early adulthood, and particularly later social anxiety disorder. Little is known about the relevance of potential prenatal precursors and early predictors for the development of inhibited behavior, such as infant vulnerability and family risk factors like parental anxiety and overprotection. Pregnancy-related anxiety has been associated with both infant temperament and maternal overprotective parenting. Thus, the aim of this study was investigating the predictive relevance of prenatal pregnancy-related anxiety for behavioral inhibition in toddlerhood, by considering the mediating role of maternal overprotection and infant distress to novelty.

Materials and Methods

As part of a longitudinal pregnancy cohort, behavioral inhibition at 24 months postpartum was assessed in N = 170 mother-child pairs. Maternal pregnancy-related anxiety was examined in the third trimester of pregnancy, and maternal overprotection and infant distress to novelty at 12 months postpartum.

Results

Mediation analysis with two parallel mediators showed that the significant direct effect of pregnancy-related anxiety on child behavioral inhibition was fully mediated by infant distress to novelty p < 0.001 and maternal overprotection (p < 0.05). The included variables explained 26% of variance in behavioral inhibition. A subsequent explorative mediation analysis with serial mediators further showed a significant positive association between distress to novelty and maternal overprotective parenting (p < 0.05).

Conclusion

Results indicate a predictive relevance of both infant and maternal factors for the development of behavioral inhibition in toddlerhood. Mothers who perceived more pregnancy-related anxiety showed more overprotective parenting and had infants with more distress to novelty. Further, mothers being more overprotective reported their child to be more inhibited in toddlerhood. Our findings also indicate the stability of reported infant distress to novelty as one aspect of later behavioral inhibition. Addressing specific forms of parental anxiety from pregnancy on and in interaction with child-related variables seems to be a promising approach for future studies and clinical interventions.

Prenatal PM2.5 exposure and infant temperament at age 6 months: Sensitive windows and sex-specific associations

BACKGROUND

Prenatal exposure to fine particulate matter with a diameter of ≤2.5 μm (PM2.5) has been linked to adverse neurodevelopmental outcomes in later childhood, while research on early infant behavior remains sparse.

OBJECTIVES

We examined associations between prenatal PM2.5 exposure and infant negative affectivity, a stable temperamental trait associated with longer-term behavioral and mental health outcomes. We also examined sex-specific effects.

METHODS

Analyses included 559 mother-infant pairs enrolled in the PRogramming of Intergenerational Stress Mechanisms (PRISM) cohort. Daily PM2.5 exposure based on geocoded residential address during pregnancy was estimated using a satellite-based spatiotemporal model. Domains of negative affectivity (Sadness, Distress to Limitations, Fear, Falling Reactivity) were assessed using the Infant Behavior Questionnaire-Revised (IBQ-R) when infants were 6 months old. Subscale scores were calculated as the mean of item-specific responses; the global Negative Affectivity (NA) score was derived by averaging the mean of the four subscale scores. Bayesian distributed lag interaction models (BDLIMs) were used to identify sensitive windows for prenatal PM2.5 exposure on global NA and its subscales, and to examine effect modification by sex.

RESULTS

Mothers were primarily racial/ethnic minorities (38% Black, 37% Hispanic), 40% had ≤12 years of education; most did not smoke during pregnancy (87%). In the overall sample, BDLIMs revealed that increased PM2.5 at mid-pregnancy was associated with higher global NA, Sadness, and Fear scores, after adjusting for covariates (maternal age, education, race/ethnicity, sex). Among boys, increased PM2.5 at early pregnancy was associated with decreased Fear scores, while exposure during late pregnancy was associated with increased Fear scores (cumulative effect estimate = 0.57, 95% CI: 0.03-1.41). Among girls, increased PM2.5 during mid-pregnancy was associated with higher Fear scores (cumulative effect estimate = 0.82, 95% CI: 0.05-1.91).

CONCLUSIONS

Prenatal PM2.5 exposure was associated with negative affectivity at age 6 months, and the sensitive windows may vary by subdomains and infant sex.

Early Childhood Temperamental Trajectories following Very Preterm Birth and Their Association with Parenting Style

Childhood temperament is an early characteristic shaping later life adjustment. However, little is currently known about the stability of early temperament and its susceptibility to the environment in children born very preterm (VPT; <33 weeks’ gestation). Here, we investigated infant-to-childhood temperamental trajectories, and their interaction with parental practices, in VPT children. Maternal reports of infant temperament were collected in 190 infants (mean age: 11.27 months; range 9−18 months) enrolled in the longitudinal Evaluation of Preterm Imaging (ePrime; Eudra: CT 2009-011602-42) study, using the ePrime questionnaire on infant temperament. At 4−7 years of age, further assessments of child temperament (Children’s Behavior Questionnaire—Very Short Form) and parenting style (Arnold’s Parenting Scale) were conducted. Results showed that more difficult temperament in infancy was associated with increased Negative Affectivity in childhood, regardless of parenting practices. This lends support to the stability of early temperamental traits reflecting negative emotionality. In contrast, a lax parenting style moderated the relationship between easy infant temperament and Negative Affectivity at 4−7 years, such that an easier infant temperament was increasingly associated with higher childhood Negative Affectivity scores as parental laxness increased. These results highlight a potential vulnerability of VPT infants considered by their mothers to be easy to handle, as they may be more susceptible to the effects of suboptimal parenting in childhood.

Infant Developmental Outcomes: Influence of Prenatal Maternal-Fetal Attachment, Adult Attachment, Maternal Well-Being, and Perinatal Loss

Identification of prenatal characteristics that predict later infant development may afford opportunities for early intervention, potentially optimizing childhood development outcomes. The aim of the present study was to examine the effects of selected prenatal factors (maternal–fetal attachment, maternal adult attachment, maternal well-being, and previous perinatal loss) on later infant development. Pregnant women were recruited from two antenatal clinics at one tertiary hospital and asked to complete self-report questionnaires. The Bayley’s Scales of Infant and Toddler Development were then completed one to two years after their baby’s birth. Independent samples t-tests, correlational analyses, and multivariate linear regression models were conducted. Results from 40 dyads revealed that more favorable maternal–fetal attachment, more secure/less anxious maternal attachment, and higher maternal well-being predicted maternal reports of infant adaptive behavior regardless of previous perinatal loss. Infants of women without perinatal loss scored higher in external observer-rated cognitive development compared to infants of women with previous perinatal loss. While further research is required, findings indicate that a mother’s well-being and her relationship with her baby during pregnancy contributes to positive perceptions of her infant’s daily living skills. Supporting the parenting of women with perinatal loss is required to, in turn, promote optimal cognitive development in infants.

Maternal Mood and Perception of Infant Temperament at Three Months Predict Depressive Symptoms Scores in Mothers of Preterm Infants at Six Months

Postpartum depression is more prevalent in mothers and fathers of preterm infants compared to parents of full-term infants and may have long-term detrimental consequences for parental mental health and child development. The temperamental profile of an infant has been postulated as one of the important factors associated with parental depressiveness in the first months postpartum. This study aimed to examine the longitudinal relationship between depressive symptoms and perceived infant temperament at 3 months corrected age, and depressive symptoms at 6 months corrected age among mothers and fathers of infants born preterm. We assessed 59 families with infants born before the 34th gestational week using the Edinburgh Postnatal Depression Scale (EDPS) and the Infant Behavior Questionnaire-Revised. We found that mothers’ scores on EPDS and infants’ Orienting/regulation at 3 months corrected age predicted mothers’ EPDS scores at 6 months corrected age. In particular, higher depressive scores were related to higher depressive symptoms at 6 months corrected age, whereas higher infant Orienting/regulation was related to lower depressive symptoms at 6 months corrected age. Due to the low internal consistency of EPDS at 6 months for fathers, we were unable to conduct similar analyses for fathers. Our results point to the importance of considering both early indices of maternal mood as well as mother-reported measures of preterm infant temperament in the attempts to predict levels of maternal depressiveness in later months of an infant’s life. Further studies are urgently needed in order to better understand the associations between depressiveness and infant temperament in fathers, and with more consideration for the severity of the effects of infant prematurity.

Longitudinal Temperament Pathways to ADHD Between Childhood and Adolescence

The current investigation extended prior cross-sectional mapping of etiological factors, transdiagnostic effortful and affective traits, and ADHD symptoms to longitudinal pathways extending from two etiological domains: polygenic and prenatal risk. Hypotheses were (1) genetic risk for ADHD would be related to inattentive ADHD symptoms in adolescence and mediated by childhood effortful control; (2) prenatal smoking would be related to hyperactive-impulsive ADHD symptoms during childhood and mediated by childhood surgency; and (3) there would be age-related variation, such that mediation of genetic risk would be larger for older than younger ages, whereas mediation of prenatal risk would be larger in earlier childhood than at later ages. Participants were 849 children drawn from the Oregon ADHD-1000 Cohort, which used a case control sample and an accelerated longitudinal design to track development from childhood (at year 1 ages 7-13) through adolescence (at year 6 ages 13-19). Results showed the mediational pathway from prenatal smoking through surgency to hyperactivity-impulsivity at Year 1 was significant (indirect effect estimate = .053, p < .01). The mediational pathway from polygenic risk through effortful control to inattention at Year 6 was also significant (indirect effect estimate = .084, p < .01). Both results were independent of the association between inattention and hyperactivity-impulsivity and control for the alternative etiological input and held across parent- and teacher-report of ADHD symptoms. In line with dual pathway models of ADHD, early prenatal risk for hyperactivity-impulsivity appears to operate through surgency, while polygenic genetic risk for inattention appears mediated by effortful control.