Maternal perceived discrimination and association with gestational diabetes

BACKGROUND: Maternal psychosocial stress, including experiences of discrimination, has been linked to adverse pregnancy outcomes. Perceived discrimination may activate the chronic stress response, the downstream effects of which include dysregulation of metabolic and immune systems. The effect of perceived discrimination on the development of gestational diabetes mellitus, a metabolic disorder of pregnancy, has not been evaluated. OBJECTIVE: This study aimed to evaluate the association between perceived maternal discrimination and incidence of gestational diabetes mellitus. STUDY DESIGN: A prospective cohort study of 744 pregnant women was conducted from 2013 to 2015 at 4 sites in the United States. Participants were women who were ≥18 years old with a singleton pregnancy, <21 weeks pregnant when recruited into the study, and English speaking without fetal anomalies, progesterone treatment, or corticosteroid use during pregnancy. Women with pregestational diabetes were excluded from the study. Participants with a gestational age between 12 0/7 and 20 6/7 weeks completed the Williams Discrimination Scale. For this analysis, Williams Discrimination Scale scores were dichotomized at the 75th percentile. We estimated the association between scoring in the top quartile of the Williams Discrimination Scale and developing gestational diabetes mellitus using logistic regression. As obesity is an independent risk factor for developing gestational diabetes mellitus, we also used mediation methods to determine the proportion of the association mediated by prepregnancy obesity (body mass index, ≥30 kg/m2). Models were adjusted for maternal age, income, parity, race and ethnicity, and study site. RESULTS: Among the 595 eligible subjects, 368 (61.9%) were white, 99 (16.6%) black, and 93 (15.6%) Hispanic. The mean body mass index was 27.4 kg/m2 (standard deviation, 7.1 kg/m2), and 50 subjects (8.4%) developed gestational diabetes mellitus. Women with gestational diabetes mellitus were significantly more likely to be older, to be multiparous, and to have a lower income. Scoring in the top quartile of the Williams Discrimination Scale was associated with a significantly increased risk of developing gestational diabetes mellitus (12.8% vs 7.0%; adjusted odds ratio, 2.11; 95% confidence interval, 1.03-4.22). Obesity mediated 22.6% of the relationship between the Williams Discrimination Scale and gestational diabetes mellitus. CONCLUSION: Women who perceived greater discrimination had an increased risk of developing gestational diabetes mellitus. Results from the mediation analysis indicate that more than 20% of the association between discrimination and gestational diabetes mellitus operates via a pathway that includes obesity. Future studies should examine this and other mechanistic pathways that may underlie these associations.