Sleep disturbances and inflammatory gene expression among pregnant women: Differential responses by race

Incorporating machine learning and statistical methods to address maternal healthcare disparities in US: A systematic review

BACKGROUND

Maternal health disparities are recognized as a significant public health challenge, with pronounced disparities evident across racial, socioeconomic, and geographic dimensions. Although healthcare technologies have advanced, these disparities remain primarily unaddressed, indicating that enhanced analytical approaches are needed.

OBJECTIVES

This review aims to evaluate the impact of machine learning (ML) and statistical methods on identifying and addressing maternal health disparities and to outline future research directions for enhancing these methodologies.

METHODS

Following the PRISMA guidelines, the review of studies employing ML and statistical methods to analyze maternal health disparities within the United States was conducted. Publications between January 1, 2012, and February 2024 were systematically searched through PubMed, Web of Science, and ScienceDirect. Inclusion criteria targeted studies conducted within the U.S., peer-reviewed articles published during the period, research covering the postpartum period up to one year post-delivery, and studies incorporating both maternal and infant health data with a focus primarily on maternal outcomes.

RESULTS

A total of 147 studies met the inclusion criteria for this analysis. Among these, 129 (88 %) utilized statistical methods in health sciences to analyze correlations, treatment effects, and public health initiatives, thus providing vital, actionable insights for policy and clinical decisions. Meanwhile, 18 articles (12 %) applied ML techniques to explore complex, nonlinear relationships in data. The findings indicate that while ML and statistical methods offer valuable insights into the factors contributing to health disparities, there are limitations regarding dataset diversity and methodological precision. Most studies concentrate on racial and socioeconomic inequalities, with fewer addressing the geographical aspects of maternal health. This review emphasizes the necessity for broader dataset utilization and methodology improvements to enhance the findings' predictive accuracy and applicability.

CONCLUSIONS

ML and statistical methods show great potential to transform maternal healthcare by identifying and addressing disparities. Future research should focus on broadening dataset diversity, improving methodological precision, and enhancing interdisciplinary efforts.

Sleep during pregnancy: A Systematic Review of Racial and Ethnic Disparities and Associations to Experiences of Discrimination

OBJECTIVE

Sleep is critical to perinatal health, with poor quality and short sleep duration in pregnancy being associated to adverse maternal outcomes (e.g., preterm birth, preeclampsia, depression), as well as increased risk for poor offspring outcomes (e.g., lower birthweight, risk for neurodevelopmental disorders). However, a growing body of work documents the existence of ethnic and racial sleep health disparities, but no reviews have examined disparities during pregnancy, a period where sleep is critical for health of the pregnant person and offspring and where stark disparities in pregnancy and delivery outcomes are also observed. We reviewed the available evidence regarding racial/ethnic disparities in prenatal sleep health and the association between exposure to racial/ethnic discrimination and prenatal sleep, a potential mechanism underlying disparities.

DATA SOURCES

PubMed, MEDLINE, EMBASE, PsycINFO, CINAHL, and ClinicalTrials.gov were searched from inception until November 3, 2023.

STUDY ELIGIBILITY CRITERIA

Peer-reviewed quantitative studies that examined 1) racial/ethnic disparities in sleep and/or 2) associations between exposure to racial/ethnic discrimination in the prenatal period.

STUDY APPRAISAL AND SYNTHESIS METHODS

The present systematic review conducted a narrative synthesis and used the National Heart, Lung, and Blood Institute Quality Assessment tool for Observational Cohort and Cross-sectional Studies.

RESULTS

Eighteen studies were included: 12 found disparities, three did not, and three documented associations between experiences of discrimination and sleep. Overall, African American/Black pregnant persons were found to experience shorter sleep duration and poorer quality, compared to White persons. Studies yielded mixed findings when examining sleep disturbances, latency, and insomnia symptoms. Findings were mixed for Hispanic/Latine persons, with some studies finding increased risk for short and long sleep duration and both increased and decreased sleep disruptions. Studies of other racial/ethnic groups were too few to draw conclusions. Associations between experiencing racial/ethnic discrimination and poorer prenatal sleep were documented across the three studies that examined the topic, but two studies had overlapping samples, precluding from conclusions.

CONCLUSIONS

Studies suggest ethnic/racial disparities in prenatal sleep, emphasizing the need for targeted interventions and support. However, important gaps remain, including poor consideration of covariates like socioeconomic status and maternal age, health conditions, and depression. Yet, studies that controlled for socioeconomic status documented disparities, suggesting disparities persist when factors like educational attainment and income are considered. There was considerable variety in how sleep was measured, contributing to the heterogeneity of findings. Our review strongly underscores the need for more research and highlights the importance of addressing social determinants of health and to achieve sleep health equity, which is critical to sustaining healthy pregnancies.

Pathways to maternal health inequities: Structural racism, sleep, and physiological stress

Racial inequities in health are vast and well-documented, particularly regarding maternal and infant health. Sleep health, including but not limited to duration and quality, is central to overall health and well-being. However, research has not adequately addressed how racism embedded in structures and systems, in addition to individual experiences, may affect maternal health by impacting sleep. In this critical review, we aim to 1) synthesize findings, emphasizing collaborative studies within our group, 2) highlight gaps in knowledge, and 3) propose a theoretical framework and methodological approach for moving the field forward. Specifically, we focus on findings and future directions linking perinatal sleep, cardiovascular and immune function, and racial disparities in maternal health. Because too few studies look beyond individual-level determinants of sleep deficiencies among Black Americans, we assert a critical need for research that bridges multiple levels of analysis (e.g., individual, community, society) and provides recommendations for specific health parameters that researchers in this area can target. Although the need to understand and address perinatal health disparities is clear, the goal of identifying multilevel mechanisms underlying how racism in one's environment and daily life may interact to affect health extends far beyond pregnancy research.

Moving toward affective immunology: Legacy and future directions

The term "affective immunology" has recently been used to denote a field focused on the interplay between affective processes (including mood states, specific emotions, and regulatory processes) and various aspects of immune function. The overarching goals of this commentary are a) to provide historical underpinnings of this field with a focus on the profound impact of the work of Janice Kiecolt-Glaser, who is further honored in this special issue, b) to review important off-shoots of her legacy work in this domain, and c) to highlight important future directions for the field. Kiecolt-Glaser's work laid much of the foundation for affective immunology, with groundbreaking research related to depression, hostility and dyadic interactions, loneliness, and other affective patterns, often in the context of holistic models, novel experimental designs, and interventions. Her former mentees (and many of their mentees) have carried on her legacy in these domains, in ways that continue to advance appreciation of how affective processes relate to immune function. There are numerous remaining questions for the field to pursue, including better understanding of the role of emotion regulation, emotional reactivity and recovery, restorative processes, affective variability, and developmental and dynamic social processes. Such work will require greater use of longitudinal and within-person approaches and/or examination of processes in daily life, as well as models that account for interactive and reciprocal processes and which integrate behavior, social context, sociocultural factors, individual differences, and other aspects of health. As more work in these domains continues, building on Kiecolt-Glaser's rich legacy, we move toward the emergence of affective immunology as an important subfield in the domain of psychoneuroimmunology, one which will offer more nuanced understanding of the role of affective processes in immune health.

Associations of maternal sleep trajectories during pregnancy and adverse perinatal outcomes: a prospective cohort study

OBJECTIVE

Sleep problems are common in pregnant women and sleep is altered during pregnancy. However, the associations between sleep trajectory patterns and adverse maternal and neonatal outcomes are unclear. The current study aims to identify sleep trajectory patterns and explore their associations with adverse perinatal outcomes in a prospective cohort study.

METHODS

Pregnant women (N = 232) completed the Pittsburgh Sleep Quality Index each trimester during pregnancy in Tianjin, China. Perinatal outcomes were extracted from the hospital delivery records. Latent class growth analysis (LCGA) described the trajectories of sleep timing, duration, and efficiency. Multivariable linear regression and multivariable logistic regression were employed to evaluate associations between sleep trajectory patterns and perinatal outcomes.

RESULTS

Trajectories were identified for bedtime (early, 49.1%; delaying, 50.9%), wake-up time (early, 82.8% of the sample; late, 17.2%), duration (short, 5.2%; adequate 78.0%; excessive, 16.8%), and efficiency (high, 88.4%; decreasing, 11.6%). Compared with women in more optimal sleep groups, those in the late wake-up, excessive duration, and decreasing efficiency groups had babies with shorter birth lengths (β range, -0.50 to -0.28, p < 0.05). Moreover, women in the decreasing efficiency group had babies with lower birth weight (β, -0.44; p < 0.05). Women in the delaying bedtime group had greater odds of preterm delivery (OR, 4.57; p < 0.05), while those in the decreasing efficiency group had greater odds of cesarean section (OR, 3.12; p < 0.05).

CONCLUSIONS

Less optimal sleep trajectory patterns during pregnancy are associated with perinatal outcomes. Therefore, early assessment of maternal sleep during pregnancy is significant for identifying at-risk women and initiating interventions to reduce perinatal outcomes.

Association between sleep quality with maternal and neonatal outcomes during the covid-19 pandemic

AIM

Sleep disorders during pregnancy can impact maternal and neonatal outcomes. The objective of this study is to examine the relationship between sleep quality and maternal and neonatal outcomes during the COVID-19 pandemic.

METHOD

This prospective cohort study was conducted at the Educational-Therapeutic Center of Shohadaye Yaftabad Referral Hospital in Tehran, Iran, from December 2020 to September 2022. A total of 198 eligible participants were randomly assigned to either the sleep disorders group or the no sleep disorders group. Data were collected through demographic questionnaires, the Corona Disease Anxiety Scale (CDAS) questionnaire, the Pittsburgh Sleep Quality Index (PSQI), and the checklist for maternal and neonatal outcomes.

RESULTS

At baseline, the sleep disorders and no sleep disorders groups were similar in terms of age, body mass index (before pregnancy), education level, employment status, gravida, parity, abortion, and history of COVID-19. Within the sleep disorders group, there was a statistically significant, direct linear correlation between sleep disorders and FBS 34-36 weeks (r = 0.33, P < 0.001) as well as Corona Disease Anxiety (CDA) (r = 0.35, P < 0.001). The linear regression results indicated that for every unit increase in sleep disorders, the risk of FBS 34-36 weeks increased by 1.09 times (β = 1.09, P < 0.001). Additionally, sleep disorders increased the risk of CDA by 1.36 times (β = 1.36, P < 0.001). The results showed no statistically significant differences in terms of birth weight, type of delivery (vaginal or cesarean section), gestational age (preterm or full term), length of labor stages (first and second stage), Apgar score at minutes 1 and 5, and NICU admission between the two groups.

CONCLUSION

Based on the results, a certain degree of correlation exists between sleep quality and FBS at 34-36 weeks and CDA. These findings underscore the need for future public health guidelines to formulate detailed strategies to improve sleep quality during the COVID-19 pandemic.

Relationship between sleep and serum inflammatory factors in patients with major depressive disorder

BACKGROUND

At present, the relationship between sleep and inflammatory factors is not clear. The aim of this study was to investigate the relationship between specific inflammatory factors and sleep in MDD patients.

METHODS

We measured and compared clinical features and 10 peripheral blood inflammatory factors in 40 MDD patients with sleep disorders, 80 MDD patients without sleep disorders, and 80 healthy controls. Correlation analysis and multiple linear regression analysis were used to explore the relationship between sleep and inflammatory factors.

RESULT

The levels of IL-1β, IL-2, IL-6, IL-8, IL-10, CRP, TNF-α, CXCL-1, CXCL-2, and IFN-γ were different among the three groups(all p<0.05).Poor sleep quality was significantly negatively correlated with IL-2 and IL-8 (all p<0.01), and significantly positively correlated with IL-6, IL-10, CRP, TNF-α, CXCL-1, CXCL-2 and IFN-γ (all p<0.01). IL-8 could significantly negatively predict the deterioration of sleep quality (p<0.001), and TNF-a and IFN-γ could significantly positively predict the deterioration of sleep quality (all p<0.05).

LIMITATIONS

The self-rating scale was used in this study.

CONCLUSIONS

Inflammatory factors are disrupted in patients with sleep disorders. The lower the level of IL-8 in peripheral blood of MDD patients, the higher the TNF-a and IFN-γ, and the worse the quality of sleep.

Sleep disturbance and activation of cellular and transcriptional mechanisms of inflammation in older adults

BACKGROUND

Sleep disturbance, including poor subjective sleep quality and insomnia disorder, is common in older adults and associated with increases in age-related morbidity risk. Accumulating evidence implicates inflammation as an underlying mechanism. In two complementary studies, we examined whether sleep disturbance is associated with activation of cellular and transcriptional mechanisms of inflammation in older adults.

METHODS

Study 1 examined whether healthy older adults with poor subjective sleep quality (n = 62), compared to those with good subjective sleep quality (n = 101), differed in monocytic production of interleukin (IL)-6 and/or tumor necrosis factor (TNF)-α following stimulation with lipopolysaccharide. Study 2 examined whether older adults with insomnia disorder (n = 17), compared to those without insomnia disorder (n = 25), differed in the regulation of transcription factors (TFs) related to immune activation (i.e., nuclear factor-κB/Rel family), sympathetic nervous system (SNS) activity (i.e., cAMP-response element-binding protein), hypothalamic-pituitary-adrenal (HPA) axis activity (i.e., glucocorticoid receptor) and anti-viral responses (i.e., interferon-regulatory factor/interferon-stimulated response element) assessed in peripheral blood mononuclear cells.

RESULTS

In Study 1, older adults with poor subjective sleep quality, compared to those with good subjective sleep quality, showed higher percentages of stimulated monocytes producing IL-6 only (25.4 ± 16.8 % vs 20.4 ± 13.9 %; p < 0.05, η_p² = 0.03), producing TNF-α only (37.6 ± 13.1 % vs 31.2 ± 14.3 %; p < 0.01, η_p² = 0.05), and co-producing IL-6/TNF-α simultaneously (17.8 ± 11.7 % vs 13.9 ± 9.6 %; p < 0.05, η_p² = 0.03). In Study 2, older adults with insomnia disorder, compared to those without insomnia disorder, showed higher TF activity related to immune activation (p's < 0.05) and SNS function (p's < 0.001), along with lower TF activity related to HPA axis function (p's < 0.05).

CONCLUSION

In older adults, poor subjective sleep quality and insomnia diagnosis are associated with increases in monocytic cytokine production and changes in TF activity related to immune activation, SNS function, and HPA axis function. Activation of markers of cellular and transcriptional inflammation might contribute to the link between sleep disturbance and age-related morbidity risk.

Maternal sleep during pregnancy and adverse pregnancy outcomes: A systematic review and meta-analysis

AIMS/INTRODUCTION

Sleep problems are important public health concern worldwide. We carried out a meta-analysis to quantitatively evaluate whether sleep duration was associated with pregnancy outcomes, and the associations were modified by important characteristics of studies.

MATERIALS AND METHODS

Based on PubMed, Embase and the Cochrane Central Register of Controlled Trials databases, we searched for published literature related to maternal sleep duration and adverse pregnancy outcomes before 30 June 2021. We carried out risk of bias assessment, subgroup analyses and sensitivity analysis. The relative risks or odds ratios with 95% confidence intervals (CI) were used to estimate the pooled effects.

RESULTS

A total of 5,246 references were identified through a database search, and 41 studies were included in the study. Pregnant women with short sleep duration had 1.81-fold (95% CI 1.35-2.44, P < 0.001) the risk of developing gestational diabetes mellitus. The association between short sleep duration and the risk of gestational hypertension, cesarean section, low birthweight, preterm birth and small for gestational age were not significant (P > 0.05). Furthermore, long sleep duration was significantly correlated with gestational diabetes mellitus (odds ratio1.24. 95% CI 1.12-1.36, P < 0.001) and CS (odds ratio 1.13. 95% CI 1.04-1.22, P = 0.004), whereas long sleep duration was not linked with gestational hypertension, low birthweight, preterm birth and small for gestational age (P > 0.05).

CONCLUSIONS

Short/long sleep duration appeared to be associated with adverse pregnancy outcomes, specifically with an increased risk of gestational diabetes mellitus. Sleep should be systematically screened in the obstetric population.

Nitric oxide-related gene and microRNA expression in peripheral blood in pregnancy vary by self-reported race

Adverse pregnancy outcomes disproportionately affect non-Hispanic (NH) Black patients in the United States. Structural racism has been associated with increased psychosocial distress and inflammation and may trigger oxidative stress. Thus, the nitric oxide (NO) pathway (involved in the regulation of inflammation and oxidative stress) may partly explain the underlying disparities in obstetric outcomes.Cohort study of 154 pregnant patients with high-risk obstetric histories; n = 212 mRNAs and n = 108 microRNAs (miRNAs) in the NO pathway were evaluated in circulating white blood cells. NO pathway mRNA and miRNA transcript counts were compared by self-reported race; NH Black patients were compared with women of other races/ethnicities. Finally, miRNA-mRNA expression levels were correlated.Twenty-two genes (q < 0.10) were differentially expressed in self-identified NH Black individuals. Superoxide dismutase 1 (SOD1), interleukin-8 (IL-8), dynein light chain LC8-type 1 (DYNLL1), glutathione peroxidase 4 (GPX4), and glutathione peroxidase 1 (GPX1) were the five most differentially expressed genes among NH Black patients compared to other patients. There were 63 significantly correlated miRNA-mRNA pairs (q < 0.10) demonstrating potential miRNA regulation of associated target mRNA expression. Ten miRNAs that were identified as members of significant miRNA-mRNA pairs were also differentially expressed among NH Black patients (q < 0.10).These findings support an association between NO pathway and inflammation and infection-related mRNA and miRNA expression in blood drawn during pregnancy and patient race/ethnicity. These findings may reflect key differences in the biology of inflammatory gene dysregulation that occurs in response to the stress of systemic racism and that underlies disparities in pregnancy outcomes.

Burden of sleep disturbance in non-Hispanic Black pregnant women

STUDY OBJECTIVES

Non-Hispanic Black pregnant women disproportionately experience poor perinatal outcomes compared to other racial/ethnic groups. Sleep disruption has emerged as a risk factor for adverse pregnancy outcomes, but there are limited data in minority pregnant women. We examined the prevalence of habitual snoring and its timing of onset with several key sleep-wake disturbances and their associations with perinatal outcomes in a cohort of non-Hispanic Black pregnant women.

METHODS

Non-Hispanic Black pregnant women in their third trimester were recruited from a large academic medical center and screened for habitual snoring and its timing relative to pregnancy, along with sleep quality, symptoms of insomnia, excessive daytime sleepiness, and daytime function. Clinical diagnoses of hypertensive disorders of pregnancy were obtained along with delivery outcomes.

RESULTS

In 235 women, the vast majority (80%) reported 3 or more sleep-wake disturbances, and almost half had at least 5 disturbances. Sixteen percent reported prepregnancy snoring and 20% reported pregnancy-onset snoring. Women with pregnancy-onset snoring had significantly increased odds of poor sleep quality (adjusted odds ratio [aOR] = 8.2), trouble staying asleep (aOR = 3.6), waking up too early (aOR = 2.7), excessive daytime sleepiness (aOR = 2.3), and poor daytime function (aOR = 8.7) but no relationship with perinatal outcomes. In contrast, prepregnancy snoring was related to chronic hypertension, preterm delivery, and fetal growth restriction (aOR = 2.6, aOR = 2.8, and aOR = 5.1, respectively).

CONCLUSIONS

Sleep-wake disturbances confer a significant burden to pregnant non-Hispanic Black women, an infrequently studied yet disproportionately affected population. Contributions of maternal sleep to racial disparities in perinatal health should be a priority for public health research.

CITATION

White KM, Dunietz GL, Pitts DS, Kalmbach DA, Lucchini M, O'Brien LM. Burden of sleep disturbance in non-Hispanic Black pregnant women. J Clin Sleep Med. 2022;18(5):1319-1325.

The role of inflammation in the pathogenesis of perinatal depression and offspring outcomes

The role of inflammation in the pathogenesis of depression is becoming increasingly apparent, but its role in perinatal depression is less well-studied. Pregnancy and the postpartum are characterised by distinct and changing inflammatory profiles throughout, which makes the study of depression-related alterations in this period complex. This review presents literature discussing a role for the immune system in both antenatal and postnatal depression. Furthermore, literature investigating the role of the maternal immune system on breast milk composition and offspring immunological and behavioural outcomes is discussed, before concluding with suggestions for future work as this developing field grows.

Sleep Disruption, Fatigue, and Depression as Predictors of 6-Year Clinical Outcomes Following Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

Allogeneic hematopoietic cell transplantation (HCT) is a widely used treatment for hematologic cancers, with survival rates ranging from 25% to 78%. Known risk factors for chronic graft-versus-host disease (cGVHD), a serious and common long-term complication, disease relapse, and mortality following HCT have been identified, but much of the variability in HCT outcomes is unexplained. Biobehavioral symptoms including depression, sleep disruption, and fatigue are some of the most prevalent and distressing for patients; yet research on biobehavioral risk factors for HCT outcomes is limited. This study evaluated patient-reported depression, sleep disruption, and fatigue as risk factors for cGVHD, disease relapse, and mortality.

METHODS

Adults receiving allogeneic HCT for a hematologic malignancy (N = 241) completed self-report measures of depression symptoms, sleep quality, and fatigue (severity, interference) pre-HCT and 100 days post-HCT. Clinical outcomes were monitored for up to 6 years.

RESULTS

Cox proportional hazard models (2-tailed) adjusting for patient demographic and medical characteristics revealed that high pre-HCT sleep disruption (Pittsburgh Sleep Quality Index >9; hazard ratio [HR] = 2.74, 95% confidence interval [CI] = 1.27 to 5.92) and greater post-HCT fatigue interference (HR = 1.32, 95% CI = 1.05 to 1.66) uniquely predicted increased risk of mortality. Moderate pre-HCT sleep disruption (Pittsburgh Sleep Quality Index 6-9) predicted increased risk of relapse (HR = 1.99, 95% CI = 1.02 to 3.87). Biobehavioral symptoms did not predict cGVHD incidence.

CONCLUSIONS

Biobehavioral symptoms, particularly sleep disruption and fatigue interference, predicted an increased risk for 6-year relapse and mortality after HCT. Because these symptoms are amenable to treatment, they offer specific targets for intervention to improve HCT outcomes.

Data-Driven Modeling of Pregnancy-Related Complications

A healthy pregnancy depends on complex interrelated biological adaptations involving placentation, maternal immune responses, and hormonal homeostasis. Recent advances in high-throughput technologies have provided access to multiomics biological data that, combined with clinical and social data, can provide a deeper understanding of normal and abnormal pregnancies. Integration of these heterogeneous datasets using state-of-the-art machine-learning methods can enable the prediction of short- and long-term health trajectories for a mother and offspring and the development of treatments to prevent or minimize complications. We review advanced machine-learning methods that could: provide deeper biological insights into a pregnancy not yet unveiled by current methodologies; clarify the etiologies and heterogeneity of pathologies that affect a pregnancy; and suggest the best approaches to address disparities in outcomes affecting vulnerable populations.

Pregnancy associated epigenetic markers of inflammation predict depression and anxiety symptoms in response to discrimination

Latina mothers, who have one of the highest fertility rates among ethnic groups in the United States (US), often experience discrimination. Psychosocial influences during pregnancy, such as discrimination stress, promotes inflammation. However, the role of epigenetic markers of inflammation as a mediator between, and predictor of, maternal discrimination stress and neuropsychiatric outcomes has not been extensively studied. The current study investigates the role of DNA methylation at FOXP3 Treg-cell-specific demethylated region (TSDR), as a marker of regulatory T (Treg) cells that are important negative regulators of inflammation, and the promoter of tumour necrosis factor-alpha (TNF-α) gene, an important pro-inflammatory cytokine, in relation to discrimination stress during pregnancy and depression and anxiety symptomatology.

A sample of 148 Latina women residing in the US (mean age 27.6 years) were assessed prenatally at 24–32 weeks’ gestation and 4–6 weeks postnatally for perceived discrimination exposure (Everyday Discrimination Scale, EDS), emotional distress (depression, anxiety, perinatal-specific depression), acculturation, and acculturative stress. DNA methylation levels at the FOXP3 and TNFα promoter regions from blood samples collected at the prenatal stage were assessed by bisulphite pyrosequencing.

Regression analyses showed that prenatal EDS associated with postnatal emotional distress, depression and anxiety symptoms only in those individuals with higher than mean levels of FOXP3 TSDR and TNFα promoter methylation; no such significant associations were found in those with lower than mean levels of methylation for either. We further found that these relationships were mediated by TNFα only in those with high FOXP3 TSDR methylation, implying that immunosuppression via TNFα promoter methylation buffers the impact of discrimination stress on postpartum symptomatology. These results indicate that epigenetic markers of immunosuppression and inflammation play an important role in resilience or sensitivity, respectively, to prenatal stress.