Perinatal determinants of neonatal hair glucocorticoid concentrations

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.

Preterm birth as a determinant of neurodevelopment and cognition in children (PRENCOG): protocol for an exposure-based cohort study in the UK

INTRODUCTION

Preterm birth (PTB) is strongly associated with encephalopathy of prematurity (EoP) and neurocognitive impairment. The biological axes linking PTB with atypical brain development are uncertain. We aim to elucidate the roles of neuroendocrine stress activation and immune dysregulation in linking PTB with EoP.

METHODS AND ANALYSIS

PRENCOG (PREterm birth as a determinant of Neurodevelopment and COGnition in children: mechanisms and causal evidence) is an exposure-based cohort study at the University of Edinburgh. Three hundred mother-infant dyads comprising 200 preterm births (gestational age, GA <32 weeks, exposed) and 100 term births (GA >37 weeks, non-exposed), will be recruited between January 2023 and December 2027. We will collect parental and infant medical, demographic, socioeconomic characteristics and biological data which include placental tissue, umbilical cord blood, maternal and infant hair, infant saliva, infant dried blood spots, faecal material, and structural and diffusion MRI. Infant biosamples will be collected between birth and 44 weeks GA.EoP will be characterised by MRI using morphometric similarity networks (MSNs), hierarchical complexity (HC) and magnetisation transfer saturation imaging (MTsat). We will conduct: first, multivariable regressions and statistical association assessments to test how PTB-associated risk factors (PTB-RFs) relate to MSNs, HC and or MTsat; second, structural equation modelling to investigate neuroendocrine stress activation and immune dysregulation as mediators of PTB-RFs on features of EoP. PTB-RF selection will be informed by the variables that predict real-world educational outcomes, ascertained by linking the UK National Neonatal Research Database with the National Pupil Database.

ETHICS AND DISSEMINATION

A favourable ethical opinion has been given by the South East Scotland Research Ethics Committee 02 (23/SS/0067) and NHS Lothian Research and Development (2023/0150). Results will be reported to the Medical Research Council, in scientific media, via stakeholder partners and on a website in accessible language (https://www.ed.ac.uk/centre-reproductive-health/prencog).

The association between maternal prenatal hair cortisol concentration and preterm birth: A systematic review and meta-analysis

BACKGROUND

The risk of preterm birth (PTB) increases when experiencing stress during pregnancy. Chronic stress has been associated with a dysregulation of the hypothalamic-pituitary-adrenal axis, for which hair cortisol concentration (HCC) is a promising biomarker. However, previous studies on the association between HCC and PTB yielded inconsistent results. This systematic review and meta-analysis synthesized previous studies on the association between maternal HCC before and during pregnancy and spontaneous PTB.

METHODS

Data was extracted from N = 11 studies with k = 19 effect sizes retrieved from PubMed, Embase, Web of Science, CINAHL and citation searching by hand in June 2023 and updated in October 2023. Standardized mean differences were calculated, and a random-effects three-level meta-analysis was conducted. Effect heterogeneity was assessed using Q and I2.

RESULTS

HCC during pregnancy was higher among PTB than term groups, but effects were not statistically significant (z = 0.11, 95% CI: - 0.28, 0.51, p = .54) and total heterogeneity was high (Q16 = 60.01, p < .001, I2Total = 92.30%). After leaving out two possible outlier studies in sensitivity analyses, HCC was lower among preterm compared to term delivering groups, although not statistically significant (z = - 0.06, 95% CI: - 0.20, 0.08, p = .39) but with a substantially reduced total heterogeneity (Q12 = 16.45, p = .17, I2Total = 42.15%). No moderators affected the estimates significantly, but an effect of trimester and gestational age at delivery is likely.

CONCLUSION

There is currently no evidence of prenatal HCC differences between PTB and term groups as effects were small, imprecise, and not significant. Low statistical power and methodological weaknesses of the small-scale studies challenge possible biological inferences from the small effects, but further research on HCC during pregnancy is highly encouraged.

The Association Between Pre-Pregnancy and First-Trimester Hair Cortisol and Preterm Birth: A Causal Inference Model

Background Adverse life events and chronic psychological distress before and during pregnancy have frequently been associated with preterm birth (PTB) but the biological underpinnings remain unclear. We investigated the association between corticosteroid levels in pre-pregnancy and first-trimester hair and the risk of PTB. Methods We followed 1,808 pregnant women from a prospective pre-birth cohort study in Lima, Perú. Hair samples were taken at the end of the first pregnancy trimester. The two most proximal 3cm segments to the scalp (representing pre-pregnancy and first-trimester) were analyzed to obtain hair cortisol and cortisone concentrations (HCC and HCNC). PTB was defined as birth < 37 completed gestational weeks. We constructed four generalized propensity scores for pre-pregnancy and first-trimester HCC and HCNC to create corresponding inverse probability weights before fitting marginal structural models for estimating the effect of HCC and HCNC on PTB risk. Results Pre-pregnancy Log HCC was not independently associated with PTB risk (RR = 0.97; 95%CI: 0.79, 1.19). In contrast, one SD increase from the mean first-trimester Log HCC was independently associated with a 37% (95%CI: 1.11, 1.69) increased risk of PTB. Although imprecise, pre-pregnancy Log HCNC was negatively associated with PTB risk (RR = 0.84; 95%CI: 0.58, 1.20), whereas the association between first-trimester Log HCNC and PTB risk was positive (RR = 1.20; 95%CI: 0.87, 1.65). Conclusions Our findings show that chronic corticosteroid levels in early pregnancy are causally linked to PTB risk in pregnant Peruvian women. This finding contributes to understanding the biological underpinnings of PTB better to enhance PTB prevention.

Longitudinal effects of maternal depressive and anxious symptomatology on child hair cortisol and cortisone from pregnancy to 5-years: The EDEN mother-child cohort

Exposure to maternal depressive and anxious symptomatology in utero and after birth can affect child outcomes. One proposed mechanism is through changes in child stress hormone levels, however current studies present inconsistent findings, and further research is needed to better understand the impact of maternal mental health on child stress response. This study aims to add to the limited literature by analysing longitudinal data ranging from 24 weeks amenorrhea to 5 years postpartum among 281 mother-child pairs from the French EDEN mother-child birth cohort. Hair cortisol and cortisone data were collected from children at four time points: birth, 1, 3, and 5 years. Mothers reported depressive symptomatology via the Center for Epidemiologic Studies Depression Scale (CES-D) (at 24-weeks amenorrhea, 3-, and 5-year follow-up), and the Edinburgh Postnatal Depression Scale (EPDS) (at 4, 8 and 12 months postpartum). Prenatal anxiety symptomatology was measured via the State Anxiety Inventory (STAI) at 24 weeks amenorrhea. Group-based trajectory modelling indicated a 1-cluster classification of longitudinal child hair cortisol, cortisone and cortisol-to-cortisone ratio, as analyses did not reveal a classification by subgroups representing different child profiles. After inverse probability weighting, small effects showed prenatal depressive symptomatology was significantly associated to higher levels of child hair cortisone at one year. Prenatal anxiety symptomatology was significantly linked to higher levels of child cortisol measured at birth and cortisone at birth and at 1 year. Postpartum depressive symptomatology at 8 months was related to higher levels of cortisone among 3-year-olds. These effects were not moderated by child sex or maternal socio-economic status. Further research is needed to understand why there are associations at some time points and not others to determine any potential buffering factors.

Hair and plasma cortisol throughout the first 3 years of development in infant rhesus macaques, Macaca mulatta

Cortisol expression has been demonstrated to have variation across development in rhesus macaques (Macaca mulatta). There exists contradictory evidence for the nature of this change, and age at which it occurs, across biological sample types. Consequently, we lack a cohesive understanding for cortisol concentrations across the development of a major human health translational model. We examined hair cortisol concentrations over the first 3 years of life for 49 mother-reared infant macaques from mixed-sex outdoor units at the California National Primate Research Center. For 48 of these subjects at infancy, 1 year, and 2 years, we obtained plasma cortisol samples for response to a stressor, adjustment to prolonged stress, and response to dexamethasone injection. Hair cortisol concentrations decreased dramatically between 3 and 10 months, followed by relative stability up to the final sampling event at around 34 months of age. Plasma cortisol showed within-year consistency, and consistency between infancy and year 1. We document variability in the infant plasma cortisol samples, especially in percent change between samples 1 and 2. Our plasma cortisol results indicate that infants possess the physiological capacity to effectively inhibit the release of cortisol when stimulated, as effectively as later responses in juveniles. Age-related changes in hair cortisol parallel findings indicating a large decline in the weeks following postparturation.

Hair as an alternative matrix to assess exposure of premature neonates to phthalate and alternative plasticizers in the neonatal intensive care unit

Due to adverse health effects, di-(2-ethylhexyl) phthalate (DEHP), a plasticizer used to soften plastic medical devices (PMDs), was restricted, and gradually replaced by alternative plasticizers (APs). Up to this date, urine was the sole matrix studied for plasticizer exposure in neonates hospitalized in the neonatal intensive care unit (NICU), a population highly vulnerable to toxic effects of plasticizers. The primary aim of this study was to assess simultaneous measurement of phthalate and AP metabolites in neonatal scalp hair. In addition, we aimed to use this matrix to investigate exposure of premature neonates to plasticizers during their stay in the NICU. Hair samples in this study were collected from premature neonates and their mothers included in a prospective birth cohort study in a tertiary NICU at the Antwerp University Hospital (UZA), Belgium. Samples from premature neonates (n = 45) and their mothers (n = 107) as well as from control neonates (n = 24) and mothers (n = 29) were analyzed using liquid-chromatography coupled to tandem mass spectrometry. This is the first study reporting metabolites of phthalate and alternative plasticizers in neonatal hair samples as biomarkers for exposure to these plasticizers. Results showed that hair sampled from premature neonates after a NICU stay contained significantly higher metabolite concentrations of both phthalates (DEHP, DiBP, and DnBP; 9.0-2500, 9.3-2200, and 24.7-5300 ng/g), and alternative plasticizers (DEHA, DEHT, and TOTM; 38.8-3400, 127.5-5700, and 10.8-8700 ng/g) - when compared to healthy control neonates. Besides, DEHP and DEHT metabolite concentrations were significantly higher than in hair sampled from adult populations. In addition, prolonged NICU exposure to non-invasive respiratory support devices and gastric tubes was correlated with increased concentrations in hair samples, indicating accumulation of plasticizers in this alternative matrix. In conclusion, our data indicate that preterm neonates are still highly exposed to phthalate and alternative plasticizers during NICU stay, despite the EU Medical Devices Regulation.

Correlates of preconception and pregnancy hair cortisol concentrations

Assessing factors that influence chronic stress biomarkers like hair cortisol concentrations (HCCs) in pregnancy is critical to prevent adverse pregnancy outcomes. Thus, we aimed to identify correlates of HCC preconception and during pregnancy. 2,581 pregnant women participated in the study. HCC was available at four time periods: pre-pregnancy (0-3 months preconception, n = 1,023), and in the first (1-12 weeks, n = 1,734), second (13-24 weeks, n = 1,534), and third (25-36 weeks, n = 835) trimesters. HCC was assessed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Sociodemographic, pregnancy- and hair-related characteristics, and measures of psychosocial stress, were interrogated as potential correlates of HCC. Spearman correlations, paired t-tests, and ANOVA were used to assess differences in log-transformed values of HCC (logHCC) across maternal characteristics. Multivariable linear regressions were used to identify the correlates of HCCs after adjusting for confounders. Mean logHCC values increased across the four prenatal periods (P < 0.001). In multivariable analyses, pre-pregnancy BMI was consistently associated with all HCCs, while gestational age, economic hardship, hair dyeing, and depression, showed time-specific associations with HCC. In conclusion, this study showed evidence of factors influencing HCC levels before and during pregnancy. The most consistent association was seen with pre-pregnancy BMI. Depression was also associated with HCC concentrations.

Comparative steroid profiling of newborn hair and umbilical cord serum highlights the role of fetal adrenals, placenta, and pregnancy outcomes in fetal steroid metabolism

Previous steroid hormone studies concerning pregnancy and newborns have mainly focused on glucocorticoids; wider steroid profiles have been less commonly investigated. Here, we performed a comparative analysis of 17 steroids from newborn hair and umbilical cord serum at the time of delivery. The study participants (n = 42, 50% girls) were a part of the Kuopio Birth Cohort and represent usual Finnish pregnancies. The hair and cord serum samples were analyzed with liquid chromatography high resolution mass spectrometry and triple quadrupole tandem mass spectrometry, respectively. We detected high individual variations in steroid hormone concentrations in both sample matrices. The concentrations of cortisol (F), corticosterone (B), estrone (E1), estradiol (E2), dehydroepiandrosterone (DHEA), 11β-hydroxyandostenedione (11bOHA4), 5α-androstanedione (DHA4), and 17α-hydroxypregnenolone (17OHP5) correlated positively between cord serum and newborn hair samples. In addition, F and 11bOHA4 concentrations correlated positively with each other in both newborn hair and cord serum samples. The cortisone-to-cortisol ratio (E/F) was significantly higher in cord serum than in newborn hair samples reflecting high placental 11βHSD2 enzyme activity. Only minor sex differences in steroid concentrations were observed; higher testosterone (T) and 11-deoxycortisol (S) with lower 11bOHA4 in male cord serum, and higher DHEA, androstenedione (A4) and 11bOHA4 in female newborn hair samples. Parity and delivery mode were the most significant pregnancy- and birth-related parameters associating with F and some other adrenocortical steroid concentrations. This study provides novel information about intrauterine steroid metabolism in late pregnancy and typical concentration ranges for several newborn hair steroids, including also 11-oxygenated androgens.

The association between maternal symptoms of depression and hair glucocorticoids in infants across the perinatal period

BACKGROUND

Maternal symptoms of depression constitute an early adversity for infants that is considered to exert its effects via the maternal-placental-fetal neuroendocrine axis. Previous research implicates associations between maternal prenatal symptoms of depression and infants' glucocorticoid (GC) levels shortly after birth. To date, associations have not been investigated in the early postnatal period. The current study aimed to investigate the influence of maternal perinatal symptoms of depression on infants' neonatal and postnatal hair GCs providing a retrospective reflection of integrated cortisol secretion in the intrauterine and early postnatal period, respectively.

METHODS

As part of a prospective cohort study, hair samples of infants were taken up to two weeks after delivery (N = 152) and again eight weeks after delivery (N = 165). Liquid chromatography-tandem mass spectrometry was used to determine hair cortisol and cortisone in scalp-near 2-cm hair segments. Maternal symptoms of depression were assessed during pregnancy and eight weeks postnatally based on the Edinburgh Postnatal Depression Scale.

RESULTS

Higher maternal prenatal symptoms of depression showed a significant association with higher infants' neonatal hair cortisol, when controlling for confounding variables (i.e., gestational age, mode of delivery, parity, storage time, pregnancy complications). A non-significant trend for this effect was found for the hair cortisol-to-cortisone ratio while no effect occurred for hair cortisone. No association of maternal postnatal symptoms of depression with infants' postnatal hair GCs was observed. Further exploratory analyses revealed no relationship between a change of maternal prenatal to postnatal symptoms of depression with the change from infants' neonatal to postnatal hair GC levels or postnatal hair GCs.

CONCLUSION

Our results suggest that maternal prenatal symptoms of depression are associated with dysregulated infants' hair cortisol levels mainly incorporated in the intrauterine period which, in turn, might contribute to increased susceptibility for later diseases. However, no relationship was observed in infants' hair samples additionally reflecting hair GCs of the early postnatal period. Future studies should consider research on associations between maternal symptoms of depression and infants' hair GCs also later in life and take into account additional risk factors with potential impacts on GC secretion during early infancy.

Fetal exposure to organic contaminants revealed by infant hair: A preliminary study in south China

Fetal exposure to multiple organic contaminants (OCs) is a public concern because of the adverse effects of OCs on early life development. Infant hair has the potential to be used as an alternative matrix to identify susceptible fetuses, owing to its reliability, sensitivity, and advantages associated with sampling, handling, and ethics. However, the applicability of infant hair for assessing in utero exposure to OCs is still limited. In this study, 57 infant hair samples were collected in Guangzhou, South China, to evaluate the levels and compositions of typical OCs in the fetus. Most of the target OCs were detected in infant hair, with medians of 144 μg/g, 17.7 μg/g, 192 ng/g, 46.9 ng/g, and 1.36 ng/g for phthalate esters (PAEs), alternative plasticizers (APs), organophosphorus flame retardants (OPFRs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (OCPs), respectively. Meanwhile, paired maternal hair (0-9 cm from the scalp) was collected to examine the associations between maternal and infant hair for individual compounds. Low-brominated PBDEs tended to deposit in infant hair, with median concentrations approximately two times higher than those in maternal samples. Levels of PBDEs and 4,4'-dichlorodiphenyldichloroethylene (p,p'-DDE) in paired maternal and infant hair showed strong positive correlations (p < 0.05), while most plasticizers (PAEs and APs) were poorly correlated between paired hair samples. Exposure sources were responsible for the variation in correlation between OC levels in the paired infant and maternal samples. Crude relationships between fetal exposure to OCs and birth size were examined using the Bayesian kernel machine regression (BKMR) model. BDE-28 was found to be adversely associated with the birth size. This study provides referential information for evaluating in utero exposure to OCs and their health risks based on infant hair.

Association of Plasma Cortisol Levels with Gestational Age and Anthropometric Values at Birth in Preterm Infants

There are no study reports to clarify the association between gestational age (GA) or anthropometric values at birth, and plasma cortisol levels in the blood of preterm infants at birth and at one month of age. This hospital-based retrospective cohort study included infants born at <37 weeks' gestation between 2019 and 2021. First, the association between plasma cortisol level and GA or anthropometric values at birth (birth weight standard deviation score [SDS], birth length SDS, and birth head circumference SDS) was identified by regression and multiple regression analyses. Second, plasma cortisol levels in the umbilical cord at birth and at one month of age were compared between small-for-gestational age (SGA) and non-SGA infants. Sixty-one preterm infants were enrolled (SGA: 24 and non-SGA: 37). Plasma cortisol levels at birth were significantly associated with GA. Plasma cortisol levels at one month of age were associated with GA and birth head circumference SDS. Plasma cortisol levels at birth were significantly higher in SGA than non-SGA (p = 0.010). GA was an independent determinant of plasma cortisol levels at birth. SGA infants had a high plasma cortisol level at birth; resulting in speculation that a high plasma cortisol level at birth may predict abnormal neurological outcomes.

Emotion regulation and cortisol response to the still-face procedure in preterm and full-term infants

In infancy, stress responses and emotion regulation are often coupled. Both are impacted by prematurity, though their relationship to one another in the case of infants born preterm is not fully understood. We investigated emotion regulation behaviours, cortisol reactivity and recovery and coupling between emotion regulation and cortisol reactivity to and recovery from a stressor in preterm infants. 53 preterm and 67 full-term infants with mean (range) gestational age at birth 29⁺³ (24⁺⁰-31⁺⁶) and 39⁺³ (36⁺²-42⁺⁰) weeks respectively were exposed to a socio-emotional stressor, the still-face (SF) paradigm, at 9 months of age (corrected for prematurity). The duration of negative affect and self-comforting behaviours exhibited in response to the SF, coded from a 10-minute video-taped interaction, were compared between groups. Saliva was collected from a subset (20 preterm, 24 term infants) at three timepoints: pre-SF and 20- and 30-minutes post SF. Cortisol concentrations at each timepoint were compared between groups. Associations between behavioural measures and cortisol concentrations were explored. There was no significant difference in duration of self-comforting behaviour between preterm and term infants. Preterm infants spent a significantly smaller proportion of time in a negative affective state compared to term infants (0.18 vs 0.25 s, p = 0.03). Salivary cortisol concentration was significantly higher in the preterm compared to the term group 30 min post SF (2.85 vs 1.77 nmol/L, p = 0.009), though findings were no longer significant after adjusting for time of day of sampling and socioeconomic deprivation. After controlling for time of day, greater negative affect was correlated with higher cortisol concentration 30 min post SF in the full-term (r = 0.58, p = 0.004) but not the preterm group (r = -0.01, p > 0.05). Our findings suggest altered response to an acute stressor in preterm infants, manifesting as a muted emotional response, and a lack of coupling between endocrine and behavioural stress response. Replication studies in larger samples would help to further understand biological stress repose in preterm infants and its relationship to behaviour, time of day and deprivation.