Placental FKBP51 mediates a link between second trimester maternal anxiety and birthweight in female infants

Neonatal Hair Cortisol and Birth Outcomes: An Empirical Study and Meta-Analysis

OBJECTIVE

Prenatal stress physiology is often posited as a predictor of birth outcomes, including gestational age at birth and birthweight. However, research has predominantly relied on indicators in the maternal system, with few studies examining hormones of the fetal system. The current study focuses on fetal cortisol in the third trimester, as measured in neonatal hair, as a biological factor that might be associated with birth outcomes (gestational age at birth and birthweight). We report findings from two studies: a longitudinal cohort (Study 1), and a meta-analysis of the existing literature (Study 2).

METHODSSTUDY

Hair was collected for cortisol analysis from 168 neonates (55.95% female) shortly after birth. Gestational age at birth and birthweight were abstracted from medical records.

METHODSSTUDY

An exhaustive search of four databases was conducted, yielding 155 total studies for screening. Papers reporting neonatal hair cortisol (collection <2 weeks postpartum) and birth outcomes among human neonates were retained for analysis, including Study 1 results ( k = 9).

RESULTSSTUDY

Higher neonatal hair cortisol was related to longer gestation ( r = 0.28, p < .001) and higher birthweight, r = 0.16, p = .040. Sex did not moderate either association.

RESULTSSTUDY

Across the nine studies, higher neonatal hair cortisol predicted both longer gestation ( r = 0.35, p < .001, 95% confidence interval = 0.24-0.45) and higher birthweight ( r = 0.18, p = .001, 95% confidence interval = 0.07-0.28). Neonatal sex did not moderate these associations.

CONCLUSIONS

Fetal cortisol exposure in the third trimester plays a role in normative maturation of the fetus, and findings reveal that higher cortisol is associated with positive birth outcomes.

Prenatal stress impacts foetal neurodevelopment: Temporal windows of gestational vulnerability

Prenatal maternal stressors ranging in severity from everyday occurrences/hassles to the experience of traumatic events negatively impact neurodevelopment, increasing the risk for the onset of psychopathology in the offspring. Notably, the timing of prenatal stress exposure plays a critical role in determining the nature and severity of subsequent neurodevelopmental outcomes. In this review, we evaluate the empirical evidence regarding temporal windows of heightened vulnerability to prenatal stress with respect to motor, cognitive, language, and behavioural development in both human and animal studies. We also explore potential temporal windows whereby several mechanisms may mediate prenatal stress-induced neurodevelopmental effects, namely, excessive hypothalamic-pituitary-adrenal axis activity, altered serotonin signalling and sympathetic-adrenal-medullary system, changes in placental function, immune system dysregulation, and alterations of the gut microbiota. While broadly defined developmental windows are apparent for specific psychopathological outcomes, inconsistencies arise when more complex cognitive and behavioural outcomes are considered. Novel approaches to track molecular markers reflective of the underlying aetiologies throughout gestation to identify tractable biomolecular signatures corresponding to critical vulnerability periods are urgently required.

Prenatal psychological distress and 11β-HSD2 gene expression in human placentas: Systematic review and meta-analysis

BACKGROUND

The placenta acts as a buffer to regulate the degree of fetal exposure to maternal cortisol through the 11-Beta Hydroxysteroid Dehydrogenase isoenzyme type 2 (11-β HSD2) enzyme. We conducted a systematic review and meta-analysis to assess the effect of prenatal psychological distress (PPD) on placental 11-β HSD2 gene expression and explore the related mechanistic pathways involved in fetal neurodevelopment.

METHODS

We searched PubMed, Embase, Scopus, APA PsycInfo®, and ProQuest Dissertations for observational studies assessing the association between PPD and 11-β HSD2 expression in human placentas. Adjusted regression coefficients (β) and corresponding 95% confidence intervals (CIs) were pooled based on three contextual PPD exposure groups: prenatal depression, anxiety symptoms, and perceived stress.

RESULTS

Of 3159 retrieved records, sixteen longitudinal studies involving 1869 participants across seven countries were included. Overall, exposure to PPD disorders showed weak negative associations with the placental 11-β HSD2 gene expression as follows: prenatal depression (β -0.01, 95% CI 0.05-0.02, I2=0%), anxiety symptoms (β -0.02, 95% CI 0.06-0.01, I2=0%), and perceived stress (β -0.01 95% CI 0.06-0.04, I2=62.8%). Third-trimester PPD exposure was more frequently associated with lower placental 11-β HSD2 levels. PPD and placental 11-β HSD2 were associated with changes in cortisol reactivity and the development of adverse health outcomes in mothers and children. Female-offspring were more vulnerable to PPD exposures.

CONCLUSION

The study presents evidence of a modest role of prenatal psychological distress in regulating placental 11-β HSD2 gene expression. Future prospective cohorts utilizing larger sample sizes or advanced statistical methods to enhance the detection of small effect sizes should be planned. Additionally, controlling for key predictors such as the mother's ethnicity, trimester of PPD exposure, mode of delivery, and infant sex is crucial for valid exploration of PPD effects on fetal programming.

Higher prenatal anxiety predicts lower neonatal hair cortisol

BACKGROUND

Prenatal glucocorticoids are one of the most widely proposed prenatal programming mechanisms, yet few studies exist that measure fetal cortisol via neonatal hair. Neonatal hair provides a window into the fetal experience and represents cortisol accumulation in the third trimester of pregnancy. In the current study, we test the links between two types of anxiety over the course of gestation (pregnancy-related anxiety and general anxiety) with neonatal hair cortisol.

METHOD

Pregnant individuals (N = 107) and their neonates (59.8% female) participated in the current study. Prenatal pregnancy-related anxiety and general anxiety were measured using the Pregnancy Related Anxiety Scale (PRAS) and the State-Trait Anxiety Inventory (STAI), in each trimester of pregnancy. Hierarchical linear modeling was used to model the intercept and slope of each type of anxiety over gestation. Neonatal hair samples were collected shortly after birth (Median days = 1.17, IQR = 0.75-2.00).

RESULTS

Both higher pregnancy-related anxiety and general anxiety at the beginning of pregnancy and a flatter decline of pregnancy-related anxiety over gestation were associated with lower neonatal hair cortisol. After inclusion of gestational age at birth and parity as covariates, pregnancy-related anxiety (intercept: β = -0.614, p =.012; slope: β = -0.681, p =.006), but not general anxiety (intercept: β = -0.389, p =.114; slope: β = -0.302, p =.217) remained a significant predictor. Further, when both general and pregnancy-related anxiety were entered into the same model, only pregnancy-related anxiety (intercept and slope) were significant predictors of neonatal hair cortisol, indicating an association with pregnancy-related anxiety above and beyond general anxiety.

CONCLUSION

Cortisol plays a central role in maturation of fetal organ systems, and at the end of gestation, higher cortisol has beneficial effects such as promoting fetal lung maturation. Further, lower maternal cortisol is linked to less optimal cognitive development and altered brain development. As maternal higher anxiety in early pregnancy and a flatter decrease over time are both associated with lower neonatal hair cortisol, maternal pregnancy-related anxiety could be a target of future intervention efforts.

DNA Methylation Patterns of Glucocorticoid Pathway Genes in Preterm Birth Among Black Women

Preterm birth (PTB; <37 weeks gestation) rates have increased for 5 of the last 6 consecutive years in the United States. These rates are particularly alarming for U.S. non-Hispanic Black women who give birth prematurely at 1.5 times the rate of non-Hispanic White women. Previous research suggests that psychological stress is associated with PTB in Black women. However, the biological pathways by which stress alters birth timing are not clear. We examined DNA methylation (DNAm) in peripheral blood leukocytes in 6 glucocorticoid, stress-related genes in 44 (22 PTB; 22 term birth) pregnant Black women. Four cytosine-phosphate-guanine (CpG) sites were identified as differentially methylated (p < 0.05) between women with PTB and women with term births. The ability to identify stress-related biological markers that are associated with PTB among Black women would provide a critical step toward decreasing the PTB disparity among these women. Future studies should include larger sample sizes and gene expression analyses of the stress-related biological pathways to PTB.

Sex-specific association of high maternal psychological stress during pregnancy on newborn birthweight

Birthweight is an important predictor of newborn health and has been linked to maternal psychological stress during pregnancy. However, it is unclear whether prenatal stress affects birthweight similarly for both male and female infants. We used a well-established pregnancy cohort to investigate the impact of high maternal psychological stress during pregnancy on birthweight as a function of infant sex. Overall, 5702 mother-newborn pairs were analysed. Of these, 198 mothers reported high levels of stress using the Psychological Stress Measure (nine-items version; PSM-9). Maternal psychological stress was assessed between the 24^th and 28^th week of gestation and analyses were performed jointly and independently as a function of neonatal sex (separate analyses for male and female infants). Newborns exposed to high maternal psychological stress during pregnancy (a score above 26 measured using the PSM-9 questionnaire, corresponding to >97.5^th percentile) were compared to newborns of mothers who reported lower stress. ANCOVAs revealed that high levels of maternal stress during pregnancy were linked to infant birthweight as a function of infant sex. Male infants of mothers who reported high levels of stress had a greater birthweight whereas female infants had a lower birthweight under the same conditions, in comparison to mothers who did not report greater levels of stress. Although the effect size is small, these results underline the possibility that male and female fetuses may use different strategies when adapting to maternal adversity and highlight the need to consider infant sex as a moderator of the association between maternal psychological stress during pregnancy and infant birthweight.

Cardinal role of the environment in stress induced changes across life stages and generations

The stress response in rodents and humans is exquisitely dependent on the environmental context. The interactive element of the environment is typically studied by creating laboratory models of stress-induced plasticity manifested in behavior or the underlying neuroendocrine mediators of the behavior. Here, we discuss three representative sets of studies where the role of the environment in mediating stress sensitivity or stress resilience is considered across varying windows of time. Collectively, these studies testify that environmental variation at an earlier time point modifies the relationship between stressor and stress response at a later stage. The metaplastic effects of the environment on the stress response remain possible across various endpoints, including behavior, neuroendocrine regulation, region-specific neural plasticity, and regulation of receptors. The timescale of such variation spans adulthood, across stages of life history and generational boundaries. Thus, environmental variables are powerful determinants of the observed diversity in stress response. The predominant role of the environment suggests that it is possible to promote stress resilience through purposeful modification of the environment.

Associations between social adversity and young children's hair cortisol: A systematic review

Psychosocial and socioeconomic adversity in early childhood (termed 'social adversity') can have lifelong detrimental effects on health and development. Physiological stress is one proposed mechanism by which social adversity 'gets under the skin'. There is substantial research interest in whether hair cortisol, a biomarker proposed to measure the cumulative physiological stress response over time, can illustrate this mechanism. As a result, a growing number of studies have tested for associations between indicators of social adversity and child hair cortisol. The aim of this paper is to conduct a comprehensive, systematic review of the evidence for associations between indicators of social adversity and hair cortisol, specifically in young children (birth to 8 years) published any time up to 31 December 2019. The literature search identified 44 published studies that met inclusion criteria. The studies examined associations between one or more indicators of social adversity and child hair cortisol across 35 independent cohorts comprising 8370 children. Indicators of adversity examined in the identified literature included socioeconomic factors (e.g. low parental education, low income and unemployment), psychosocial factors (e.g. parent stress, poor mental health and family violence), and children's direct exposure to maltreatment, abuse and stressful events. Across all indicators of adversity, a total of 142 associations with hair cortisol were examined. Evidence of associations was limited and inconsistent; 34/142 (24%) showed evidence of a positive association between adversity and higher hair cortisol, 8/142 (6%) showed a negative association, and more than two thirds (100/142, 70%) of all examined associations were null. The collective evidence appears insufficient to conclude that there is a relationship between social adversity and hair cortisol, as a measure of physiological stress response, in young children.

Assessment of prenatal stress-related cortisol exposure: focus on cortisol accumulation in hair and nails

Prenatal stress adversely affects offspring development. Although cortisol is hypothesized to be a key mediator of stress-induced developmental deficits, determining the amount of fetal cortisol exposure produced by maternal stress has proved challenging. Current approaches, such as measuring cortisol concentrations in maternal plasma, saliva, or urine, amniotic fluid, fetal plasma, or cord blood, all have significant limitations for assessing cumulative fetal cortisol exposure over time. A recently emerging approach is to measure cortisol concentrations in maternal hair and/or newborn hair or nail samples. Maternal hair cortisol potentially shows long-term production across each trimester of pregnancy, whereas neonatal hair or nail cortisol is thought to reflect mainly third trimester hormone accumulation. This review first describes fetal adrenocortical development, placental cortisol metabolism, and the various sources of fetal cortisol exposure across pregnancy. We then summarize the results obtained from "classical" methods of assessing prenatal cortisol exposure prior to the advent of hair and nail cortisol measurement. Lastly, we discuss the initial development and validation of the hair cortisol methodology, its subsequent application to studies of chronic stress, and recent findings regarding maternal and neonatal hair or nail cortisol concentrations in relation to prenatal stress and other variables of interest.