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

Abstract

Significant health disparities exist between African Americans (AA) and European Americans (EA) in hypertension and hypertension-related disorders. Evidence suggests that this is due to impaired vasodilation in AAs. Pregnancy is a potent systemic vasodilatory state. However, differences in vasodilation between AAs and EAs have not been investigated in pregnancy. We sought to examine the effects of pregnancy on vasodilation in AA and EA women and how this might be related to discrimination and low birth weight in their offspring. Hemodynamics [blood pressure (MAP), cardiac output (CO), total peripheral resistance (TPR)] and heart rate variability (HF-HRV) were examined at baseline in 40 pregnant AAs (n = 20) and EAs (n = 20) and matched nonpregnant women (n = 40). The Experiences of Discrimination scale and birth weight were also measured in the offspring of the pregnant participants. Whereas pregnancy was associated with decreased MAP independent of race, AAs showed impaired vasodilation independent of pregnancy status as indicated by greater TPR despite greater HF-HRV. In AAs, but not EAs, reports of fewer incidences of discrimination were associated with greater TPR. Finally, the HF-HRV of EA mothers was inversely related to the birth weight of their offspring but was uncorrelated in AAs. We report novel evidence of impaired vasodilation to an endogenous vasodilatory stimulus in AAs. Higher TPR was related to discrimination in AAs and higher HF-HRV was related to low birth weight in EAs. These findings have implications for understanding the intergenerational transmission of impaired vasodilation in AAs.

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

“…While counterintuitive, this result is not uncommon to find in the literature. For example, Christian and colleagues also found an inverse association between incidences of discrimination and TPR in pregnant African Americans, while this was not true for European Americans ( Christian et al, 2020 ). In a larger study, working-class African American adults ( N = 1,974) who typically accepted unfair treatment and had reported no experience of racial discrimination had higher systolic BP compared to those who challenged unfair treatment and reported experiencing racial discrimination ( Krieger and Sidney, 1996 ).…”

Heart Rate Variability and Pregnancy Complications: Systematic Review

“…In 75% (3/4) of the studies, RMSSD, as the commonly assessed metric, had a significant negative association with fetal growth. In 1 of the studies that included White and African American women as the 2 study populations, HRV metrics did not differ with fetal growth in the African American group [ 27 ]. Also, in 1 of the studies [ 28 ], 2 case groups were included, both with impaired uterine perfusion; 1 group included poor outcome (eg, hypertensive disorder, impaired fetal growth), and the other included no poor outcomes.…”

"Dysautonomia Involvement in Maternal Cardiac Arrhythmia"

“…Thus, this peculiarity should be considered, to avoid the use of -blockers in case of decreased (less than 1) sympathovagal balance. Maternal HRV monitoring is a useful method for the detection of autonomic imbalance in pregnant women with CA [26][27][28] . We speculate that idiopathic CA in pregnancy could be a result of persistence of increased vagal activity from the first part of gestation.…”