Measures of Maternal Psycho-Social Stress and Biomarkers of Stress Response in the Maternal-Fetal Unit

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In a cohort of 500 pregnant women recruited from two San Francisco hospitals serving economically and ethnically diverse populations, we used Targeted Minimum Loss-Based Estimation (TMLE) to evaluate the association between perceptual measures of maternal psycho-social stress and two biological measures of stress response: 1) telomere length (TL) in umbilical cord blood leukocytes collected at delivery, and 2) corticotropin-releasing hormone (CRH) in maternal plasma collected during the 2nd trimester. We evaluated ten dimensions of maternal stress, derived from questionnaires: job-related, neighborhood, community standing, experience of racism, perceived stress, acute stressful events, depression, pregnancy satisfaction, nativity, and material deprivation. All domains were identified as important predictors of TL/CRH in non-parametric variable important analyses. Therefore, CRH analyses included all stressors and were adjusted for pregnancy complications, mother’s age, parity, and race/ethnicity. TL analyses were additionally adjusted for infant sex, and gestational age at birth. 30% of participants identified as Latina, 7% Black, 40% White, 16% Asian, and 7% identified as other/mixed. Less than 10% of women did not complete high-school and 60% had a bachelor’s degree or higher. Biologic factors were more important at predicting TL than stress. Conversely, stress was more important at predicting CRH than biological factors. Counter-intuitively, experiencing racism (0.15, 95% CI: 0.12-0.17) and perceived stress (0.24, 95% CI: 0.21-0.27) were associated with greater TL (expressed as the relative ratio of telomere repeat copy number to single-copy gene copy number or T/S ratio). Pregnancy complications were associated with elevated CRH (0.13, 95% CI: -0.02-0.28), while pregnancy dissatisfaction was associated with lower CRH (-0.15, 95% CI: -0.30-0.01). Results suggest complex relationships between perceived stress and response biomarkers in the maternal-fetal unit.