Discrimination and risk of spontaneous abortion in a preconception cohort study.

Discrimination may increase risk of spontaneous abortion (SAB, pregnancy loss <20 weeks' gestation) through physiological responses and limited access to resources. We examined associations between self-reported experiences of discrimination and SAB incidence among 7359 participants in Pregnancy Study Online (PRESTO), a preconception cohort study (2013-2025), of whom 80% identify as non-Hispanic White. Eligible participants were 21-45 years, assigned female at birth, and U.S. or Canadian residents. Participants completed the Williams' Everyday Discrimination and Major Experiences of Discrimination scales. We derived summary variables for frequency of everyday discrimination (range: 0 to ≥7) and number of lifetime discrimination events (range: 0 to ≥3), with higher values indicating greater discrimination. We collected SAB data on follow-up questionnaires during preconception, early and late pregnancy. We used Cox models to estimate adjusted hazard ratios (HR) and 95% CIs. Relative to no everyday discrimination, HRs for low, medium, high, and very high scores were 1.12 (95% CI: 0.95-1.31), 0.96 (95% CI: 0.81-1.12), 1.07 (95% CI: 0.91-1.27), and 1.15 (95% CI: 0.96-1.37), respectively. HRs for 1, 2, and ≥3 events of lifetime discrimination (vs. none) were 0.98 (95% CI: 0.86-1.12), 1.21 (95% CI: 1.04-1.42), and 1.19 (0.99-1.43), respectively. Lifetime experiences showing the strongest associations with SAB incidence were discrimination by police (HR = 1.24, 95% CI: 1.01-1.53), in housing (HR = 1.19, 95% CI: 0.96-1.48), and medical care (HR = 1.19, 95% CI: 1.03-1.37). SAB incidence varied by type and timing of discrimination exposure, suggesting interventions aimed at reducing the harmful effects of discrimination during preconception are warranted.