Impaired vasodilation in pregnant African Americans: Preliminary evidence of potential antecedents and consequences

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.

The Association of Racism and Discrimination in Disparities of Hypertensive Disorders of Pregnancy in the United States: An Analysis of PRAMS Data

BACKGROUND

Hypertensive disorders of pregnancy are a leading cause of maternal mortality. Racial disparities in maternal outcomes such as maternal mortality in the United States (US) are well-documented, but the relationship of racism and/or discrimination with one's risk of developing a hypertension during pregnancy (HDP) is not well-studied.

METHODS

Data from 17 sites that asked questions regarding experiences with racism and/or discrimination during pregnancy via the Pregnancy Risk Assessment Monitoring System (PRAMS) Phase 8 (2016-2020) was used. Logistic regression models were used compare the potential of stress induced HDP from perceived experiences of racism and/or discrimination versus the effect of systemic racism and/or discrimination (in healthcare settings and generally) on racial disparities in HDP diagnosis.

RESULTS

Among 9,907 live births, 18% of participants reported they were diagnosed with hypertension during pregnancy, with non-Hispanic Black individuals having the highest rate (21.8%). Regarding experiences of racism and/or discrimination, 76.4% of participants responded "yes", with all races/ethnicities studied here except non-Hispanic White individuals responding "yes" at rates higher than 89%. Perceived experiences of racism and/or discrimination did not statistically significantly affect one's odds of being diagnosed with HDP (OR = 0.94, CI: 0.74, 1.20). The disparity in odds of having hypertension during pregnancy between Non-Hispanic Black individuals and non-Hispanic White individuals was not statistically significant when perceived experiences of racism and/or discrimination were included in the model.

CONCLUSIONS

Experiences of racism and/or discrimination drive racial disparities in hypertensive disorders in pregnancy.

PUBLIC HEALTH IMPLICATIONS

It is vital to eliminate racist and discriminatory practices and behaviors to reduce maternal morbidity and mortality.

Heart Rate Variability and Pregnancy Complications: Systematic Review

BACKGROUND

The autonomic nervous system (ANS) is known as a critical regulatory system for pregnancy-induced adaptations. If it fails to function, life-threatening pregnancy complications could occur. Hence, understanding and monitoring the underlying mechanism of action for these complications are necessary.

OBJECTIVE

We aimed to systematically review the literature concerned with the associations between heart rate variability (HRV), as an ANS biomarker, and pregnancy complications.

METHODS

We performed a comprehensive search in the PubMed, Medline Completion, CINAHL Completion, Web of Science Core Collection Classic, Cochrane Library, and SCOPUS databases in February 2022 with no time span limitation. We included studies concerned with the association between any pregnancy complications and HRV, with or without a control group. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guideline was used for the review of the studies, and Covidence software was used for the study selection process. For data synthesis, we used the guideline by Popay et al.

RESULTS

Finally, 12 studies with 6656 participants were included. Despite the methodological divergency that hindered a comprehensive comparison, our findings suggest that ANS is linked with some common pregnancy complications including fetal growth. However, existing studies do not support an association between ANS and gestational diabetes mellitus. Studies that linked pulmonary and central nervous system disorders with ANS function did not provide enough evidence to draw conclusions.

CONCLUSIONS

This review highlights the importance of understanding and monitoring the underlying mechanism of ANS in pregnancy-induced adaptations and the need for further research with robust methodology in this area.

Lifetime stressor exposure, systemic inflammation during pregnancy, and preterm birth among Black American women

Although Black American mothers and infants are at higher risk for morbidity and mortality than their White counterparts, the biological mechanisms underlying these phenomena remain largely unknown. To investigate the role that lifetime stressor exposure, perceived stressor severity, and systemic inflammatory markers might play, we studied how these factors were interrelated in 92 pregnant Black American women. We also compared inflammatory marker levels for women who did versus did not go on to give birth preterm. During the early third trimester, women completed the Stress and Adversity Inventory for Adults to assess the stressors they experienced over their lifetime. Women also provided blood samples for plasma interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor (TNF)-α quantification. Preterm births were identified by medical record review. Controlling for relevant covariates, there were significant positive associations between average levels of both overall and acute perceived stressor severity and plasma IL-1β levels. Controlling for perceived stress at assessment and exposure to racial discrimination did not affect these results. Mediation models revealed that exposure to more chronic stressors was related to higher plasma IL-1β levels, as mediated by higher average levels of overall perceived stressor severity. Exposure to fewer acute stressors was related to higher plasma IL-1β levels, as mediated by higher average levels of acute perceived stressor severity. Finally, women who went on to give birth preterm had higher levels of plasma IL-6. These data thus highlight the potential importance of assessing and addressing lifetime stressor exposure among mothers before and during maternal-infant care.

Transcranial magnetic stimulation in the treatment of adolescent depression: a systematic review and meta-analysis of aggregated and individual-patient data from uncontrolled studies

Transcranial magnetic stimulation (TMS) is a non-invasive treatment for adolescent major depressive disorder (MDD). Existing evidence on the efficacy of TMS in adolescent MDD awaits quantitative synthesis. A systematic literature search was conducted, and data from eligible studies were synthesized using random-effects models. Treatment-covariate interactions were examined in exploratory analyses of individual-patient data (IPD). Systematic search of the literature yielded 1264 hits, of which 10 individual studies (2 randomized trials) were included for quantitative synthesis of mainly uncontrolled studies. Individual patient data (IPD) were available from five trials (all uncontrolled studies). Quantitative synthesis of aggregated data revealed a statistically significant negative overall standardized mean change (pooled SMCC = 2.04, 95% CI [1.46; 2.61], SE = 0.29, p < .001), as well as a significant overall treatment response rate (Transformed Proportion = 41.30%, 95% CI [31.03; 51.57], SE = 0.05; p < 0.001), considering data from baseline to post-treatment. Exploratory IPD analyses suggests TMS might be more effective in younger individuals and individuals with more severe depression, and efficacy might be enhanced with certain treatment modality settings, including higher number of TMS sessions, longer treatment durations, and unilateral and not bilateral stimulation. Existing studies exhibit methodological shortcomings, including small-study effects and lack of control group, blinding, and randomization-compromising the credibility of the present results. To date, two randomized controlled trials on TMS in adolescent depression have been published, and the only large-scale randomized trial suggests TMS is not more effective than sham stimulation. Future large-scale, randomized, and sham-controlled trials are warranted. Future trials should ensure appropriate selection of patients for TMS treatment and guide precision medicine approaches for stimulation protocols.

The Cardiovascular Conundrum in Ethnic and Sexual Minorities: A Potential Biomarker of Constant Coping With Discrimination

Background: A paradoxical profile of greater elevated sympathetic vasoconstriction (increased total peripheral resistance, TPR) and increased vagally-mediated heart rate variability (HRV) -the so-called Cardiovascular Conundrum- has been reported in African Americans (AAs) both at rest and in response to orthostasis. Whereas some authors have attributed this pattern to genetic factors, others have pointed to the potential role of coping with repeated racial discrimination.

Objective: To disentangle between these alternative explanations, we have examined the hemodynamic profile of another population that is likely to be exposed to episodes of discrimination, i.e., sexual minorities.

Methods: The first study was conducted on a sample of AAs and European Americans (EAs) with the aim of replicating previous results on the Cardiovascular Conundrum. In the second study, lesbian, gay, and bisexual (LGB) people, matched by age and sex with heterosexual participants, underwent a hemodynamic and autonomic assessment at rest and during an emotional (in the experimental group, both LGB-related and non LGB related), and a cognitive stressor.

Results: The first study confirmed a pattern of higher resting HRV, paired with higher TPR, in AAs compared to EAs. In the second study, compared to heterosexuals, the LGB group showed the Cardiovascular Conundrum pattern, characterized by greater HRV and higher TPR at baseline and a more vascular hemodynamic profile and prominent compensation deficit in response to both tasks, and particularly during the LGB-related emotional task. However, in LGB only, the vascular response was negatively correlated with perceived discrimination.

Conclusion: Present preliminary results are discussed in terms of maladaptive physiological consequences of exposure to chronic stress and the chronic use of dysfunctional emotion regulation strategies such as suppression.

Higher cardiac vagal activity predicts lower peripheral resistance 6 years later in European but not African Americans

African American (AA) individuals are at a greater risk for the development of cardiovascular complications, such as hypertension, compared with European Americans (EAs). Higher vagally mediated heart rate variability (HRV) is typically associated with lower blood pressure (BP) and total peripheral resistance (TPR). However, research has yet to examine the differential impact of HRV on longitudinal hemodynamic activity between AAs and EAs. We sought to rectify this in a sample of 385 normotensive youths (207 AAs, 178 EAs; mean age 23.16 ± 2.9 yr). Individuals participated in two laboratory evaluations spanning approximately 6 yr. Bioimpedance was used to assess HRV at time 1 and cardiac output at both time 1 and time 2. Mean arterial pressure (MAP) was measured at both time points via an automated BP machine. TPR was calculated as MAP divided by cardiac output. Results showed AAs to have higher BP and higher TPR at time 2 compared with EAs, independent of several important covariates. Also, higher HRV at time 1 significantly predicted both lower TPR and BP at time 2 among EAs only; these associations were attenuated and not significant in AAs. HRV did not significantly predict cardiac output at time 2 in the full sample or split by ethnicity. Our findings highlight that AAs show TPR mediated long-term increases in BP irrespective of resting HRV, providing a physiological pathway linking AAs with a greater risk for mortality and morbidity from hypertension and potentially other cardiovascular disease.NEW & NEWSWORTHY African Americans and European Americans differ in hemodynamics underlying long-term blood pressure regulation. Over 6 yr, African Americans show total peripheral resistance-mediated increases in blood pressure compared with European Americans. Higher heart rate variability predicts lower blood pressure and total peripheral resistance 6 yr later in European Americans but not African Americans.