Hair cortisol levels in pregnancy as a possible determinant of fetal sex: a longitudinal study

Characterization of hair cortisol concentration pre-conception and during pregnancy

BACKGROUND

The hypothalamic pituitary adrenal (HPA) axis is a system involved in stress and pregnancy regulation, and hair cortisol concentration (HCC) is a promising biomarker of its activity. Assessing factors that influence HCC in the prenatal period is critical to understand whether and how HPA axis (dys-)regulation influences maternal health and child development, particularly in high-risk populations from low- and middle-income countries (LMICs).

AIMS

This study aimed at characterizing preconception and pregnancy HCC with respect to multiple sociodemographic, pregnancy-related, and hair-related factors.

METHODS

In a sample of N = 2581 pregnant women in Perú, participants from two cohort studies provided a 6 cm scalp hair sample at three prenatal timepoints. Each hair sample was cut into two segments of 3 cm that represent cortisol secretion at four times: preconception, first-, second- and third trimester of pregnancy. Hair cortisol was extracted using liquid chromatography tandem mass spectrometry (LC-MS/MS). Spearman correlations, paired t-tests, and ANOVA were used to assess differences in log-transformed values of HCC (logHCC) across maternal sociodemographic, pregnancy-related, and hair-related factors. Multivariable linear regressions were used to examine independent associations of HCCs with selected correlates.

RESULTS

Mean logHCC values showed an increase across the four prenatal periods. Preconception BMI was consistently associated with HCC in all three trimesters, while difficulty accessing basic foods, education, hair dyeing, and infant sex showed time-specific associations with HCCs. In sensitivity analyses, we detected no substantial segment effects in the associations of HCCs with maternal characteristics.

CONCLUSION

This study is the largest to characterize HCC in pregnant women from a LMIC. Our findings provide a foundation for the use of HCC as a biomarker of prenatal HPA axis activity for future studies. This foundation may contribute to finding valid biomarkers of stress-response systems to promote maternal and child health.

A developmental framework for understanding the influence of sex and gender on health: Pediatric pain as an exemplar

Sex differences are a robust finding in many areas of adult health, including cardiovascular disease, psychiatric disorders, and chronic pain. However, many sex differences are not consistently observed until after the onset of puberty. This has led to the hypothesis that hormones are primary contributors to sex differences in health outcomes, largely ignoring the relative contributions of early developmental influences, emerging psychosocial factors, gender, and the interaction between these variables. In this paper, we argue that a comprehensive understanding of sex and gender contributions to health outcomes should start as early as conception and take an iterative biopsychosocial-developmental perspective that considers intersecting social positions. We present a conceptual framework, informed by a review of the literature in basic, clinical, and social science that captures how critical developmental stages for both sex and gender can affect children's health and longer-term outcomes. The literature on pediatric chronic pain is used as a worked example of how the framework can be applied to understanding different chronic conditions.

Cortisol in deciduous tooth tissues: A potential metric for assessing stress exposure in archaeological and living populations

OBJECTIVE

Cortisol is a glucocorticoid hormone produced by the hypothalamic-pituitary-adrenal axis that is regularly assessed in modern human and non-human populations in saliva, blood, and hair as a measure of stress exposure and stress reactivity. While recent research has detected cortisol concentrations in modern and archaeological permanent dental tissues, the present study assessed human primary (deciduous) teeth for cortisol concentrations.

MATERIALS AND METHODS

Fifty-one dentine and enamel samples from nine modern and 10 archaeological deciduous teeth were analyzed for cortisol concentrations via enzyme-linked immunosorbent assay (ELISA).

RESULTS

Detectable concentrations of cortisol were identified in 15 (of 32) dentine and 8 (of 19) enamel samples coming from modern and archaeological deciduous teeth.

CONCLUSIONS

This study is the first known analysis of cortisol from deciduous dental tissues, demonstrating the potential to identify measurable concentrations.

SIGNIFICANCE

The ability to analyze deciduous teeth is integral to developing dental cortisol methods with multiple potential future applications, including research on the biological embedding of stress in the skeleton. This study marks a key step in a larger research program to study stress in primary dentition from living and archaeological populations.

LIMITATIONS

Multiple samples generated cortisol values that were not detectable with ELISA. Minimum quantities of tissue may be required to generate detectable levels of cortisol.

SUGGESTIONS FOR FURTHER RESEARCH

Future research should include larger sample sizes and consideration of intrinsic biological and extrinsic preservation factors on dental cortisol. Further method validation and alternative methods for assessing dental cortisol are needed.

Hair cortisol as outcome parameter for psychological and neuropsychiatric interventions-a literature review

Background

Studies measuring hair cortisol concentration (HCC) have been increasingly conducted to document stress-related, endocrine changes aggregated over time. Previous studies have shown that HCC reflects abnormalities in the hypothalamic-pituitary-adrenocortical axis (HPA axis) in the context of somatic diseases, such as Cushing's syndrome. HCC variations also reveal a corresponding alteration in HPA-axis-function in mental disorders, highlighting its potential role as a biomarker for interventions targeting mental health problems.

Aims

The aim of this study was to investigate the role of HCC in various psychological and neuropsychiatric interventions and to explore the extent to which HCC can serve as a predictive or outcome parameter in such interventions by conducting a PRISMA-compliant review of the literature.

Methods

From May to July 2022, the databases Web of Science, Google Scholar, PsychINFO, and ResearchGate were systematically searched using different combinations of relevant keywords. Studies of different types that examined HCC in the context of a wide range of psychological and neuropsychiatric interventions were included. Studies in languages other than English or German and animal studies were excluded. The MMAT tool was used, to assesses the Risk of bias.

Results

The initial search identified 334 studies. After applying the inclusion and exclusion criteria, 14 publications with a total number of 1,916 participants were identified. An association between HCC and PTSD, depressive disorders, and ongoing social and family stress can be documented. The effect of relaxation techniques, mental training, CBT, or PTSD therapy on HCC has been studied with equivocal results. Some studies found decreased HCC after treatment, while others did not show a clear effect. Baseline HCC appears to be of particular importance. In some studies, higher baseline HCC was associated with increased treatment response, providing a predictive value for HCC.

Discussion

HCC is increasingly being used as a biomarker for the mapping of psychological and neuropsychiatric interventions. However, due to the wide range of study populations and interventions, results are still heterogeneous. Nevertheless, HCC seems to be an encouraging biological parameter to describe the trajectory of different interventions aimed at improving mental health.

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.

Severe cyclones and sex-specific birth outcomes in Queensland, Australia: An interrupted time-series analysis

OBJECTIVES

A male is less adaptable to biological stressors than a female fetus with consequent higher morbidity and mortality. Adverse birth outcomes increase and male livebirths decrease after environmental disasters, economic crises, and terrorist events. We hypothesized the ratio of male to female livebirths would decrease in areas affected by severe tropical cyclones (TCs) in Queensland, Australia. Additionally, in male livebirths, there would be an increase in preterm and low birthweight births. Lastly, we hypothesized that the pregnancy stage at which exposure occurred would modify the association between TC exposure and observed outcomes.

METHODS

Interrupted time series analysis was used to analyze Queensland administrative birth records from July 2007 to June 2018 for significant changes in the sex ratio at birth, measured as the proportion of male livebirths. Adjusted generalized linear models were fitted to births in areas affected by two category five TCs: cyclones Yasi (February 2011) and Marcia (February 2015). To explore male mortality and morbidity risk, additional analysis was conducted on the proportion of male stillborn, low birthweight, and preterm births. The association between estimated pregnancy stage during the TC and the proportion of male births was also analyzed.

RESULTS

Contrary to our hypothesis, increases in the proportion of male livebirths were observed following early-pregnancy exposure to cyclone Yasi and mid-pregnancy exposure to Marcia, although the latter was not statistically significant. No significant changes were observed in proportions of male stillborn, low birthweight, and preterm births.

CONCLUSIONS

This study found a significant association between severe TCs and sex ratio at birth. The stage of pregnancy at which maternal stressors were experienced modified this association. Among people exposed in early to mid-pregnancy, the proportion of male births was higher. This may be because of differential loss of females in utero. Studying sex differences in birth outcomes provides insight into in utero vulnerabilities associated with environmental stressors. Climate change is increasing the intensity and frequency of natural disasters. Understanding fetal vulnerability to environmental stressors will provide crucial information supporting early life health interventions that mitigate the immediate and long-term effects.

Associations between psychological distress and hair cortisol during pregnancy and the early postpartum: A meta-analysis

Pregnancy and the early postpartum signify a period of high stress. Perinatal stress can include psychological distress (PD), such as anxiety, depression, and stress, as well as neuroendocrine stress, indexed by activation of the hypothalamic-pituitary-adrenal (HPA) axis and the production of the hormone cortisol. Elevated PD and cortisol levels during the perinatal period can have long-term implications for the mother and child. Methodological advances have enabled the sampling of cortisol from hair, to provide a retrospective marker of HPA axis activity over several months. Despite knowing that maternal PD and HPA activity during the perinatal period independently impact health and development, research to date is unclear as to the association between maternal PD and hair cortisol. The present meta-analysis included 29 studies to assess the strength of the relation between maternal PD and hair cortisol levels during pregnancy and the early postpartum period. Several sample and methodological factors were assessed as moderators of this effect. Analyses were conducted using multilevel meta-analysis. Results of the multilevel meta-analysis indicated that the overall effect size between PD and HCC was small but not significant z = 0.039, 95% CI [- 0.001, 0.079]. Moderator analyses indicated that the strength of the association between PD and hair cortisol was moderated by pregnancy status (i.e., effects were stronger in pregnant compared to postpartum samples), timing of HCC and PD measurements (i.e., effects were larger when PD was measured before HCC) and geographic location (i.e., effects were larger in North American studies). The findings advance our understanding of the link between PD and HPA activity during the perinatal period, a time of critical impact to child development.

Cortisol levels versus self-report stress measures during pregnancy as predictors of adverse infant outcomes: a systematic review

Systematically review existing evidence to (1) identify the association between self-report stress and cortisol levels measured during pregnancy; and, (2) assess their association with adverse infant outcomes to determine which is the better predictor. A systematic review was conducted in accordance with PRISMA guidelines. Search terms focused on pregnancy, psychological stress and cortisol. Nine electronic databases were searched, in addition to reference lists of relevant papers. Eligibility criteria consisted of studies that included measurement of self-reported psychological stress, cortisol and assessed their associations with any infant-related outcome. Further limits included studies published in English or Spanish with human female participants. A meta-regression was not feasible due to differences in study samples, measurement tools employed, types of cortisol assessed and outcomes reported. A narrative synthesis was provided. 28 studies were eligible for inclusion. Convergent validity between self-report measures and cortisol was reported by three studies (range r = 0.12-0.41). Higher levels of self-report stress were significantly associated with intrauterine growth restriction (fetal biparietal diameter, low fetal head circumference, abdominal circumference), low gestational age at birth, low anthropometric measures (birth length, head circumference, length of the neonate), poor infant neurodevelopment (cognitive development) and potentially pathogenic gut microbiota (Clostridiaceae Clostridium, Haemophilus) in six studies. Higher cortisol levels were significantly associated with intrauterine growth restriction (fetal biparietal diameter, low fetal head circumference, abdominal circumference), low gestational age at birth, low infant birth weight, poor infant neurodevelopment (attention scores on the Network Neurobehavioral Scale) and low levels of potentially protective gut microbiota (Lactobacillus, Slackia and Actinobaculum) in 13 studies. Of the studies that assessed which type of measure was a better predictor of infant outcomes (n = 6), there was agreement that cortisol levels were statistically better at predicting adverse outcomes than self-reported stress. Self-report stress measures appear to be modest predictors of adverse infant outcomes in comparison to cortisol. A number of methodological limitations need to be addressed in future studies to help understand the relationship between cortisol and self-reported stress and how they are related to adverse infant outcomes.