Objective Mindfulness, food security, and health literacy are associated with glycemic control among non-pregnant people with diabetes mellitus (DM), but the association of these social determinants of health (SDoH) with DM-related perinatal health outcomes is not known. Study Design: In this prospective cohort study, English-speaking pregnant people with DM (gestational [GDM], type 1, or type 2) completed assessments of mindfulness (Mindfulness Attention Awareness Scale), food security during pregnancy (United States Household Food Security Survey Module), and health literacy (Newest Vital Sign). The primary outcome was the hemoglobin A1c (HbA1c) value within four weeks before delivery. Secondary outcomes included maternal, neonatal, and health services outcomes. Comparisons for each SDoH were performed, including for subgroups by DM type. Results: Of 238 participants, 168 (71%) had HbA1c data available. The mean age was 33.5 years (SD ±5.0), the majority identified as non-Hispanic Black (23%) or Hispanic (25%), and 49% had GDM. Among those in the cohort, mindfulness (median 2.0 [IQR 1.1] of 5) and health literacy (27% inadequate) were low, and 19% experienced food insecurity (Figure). Individuals with food insecurity were more likely to have an HbA1c ≥6.5% (39.9% vs. 22.2%, p=0.04). HbA1c ≥6.5% also was more frequent among individuals with low (below median) mindfulness or inadequate health literacy but findings did not reach the threshold for statistical significance. Food insecurity was associated with a greater frequency of preterm birth (30.4% vs. 14.1%, p< 0.01) and a lower likelihood of attending a postpartum visit (71.7% vs. 79.7%, p=0.03). SDoH were not statistically significantly associated with other secondary outcomes (Table). Findings did not differ by DM type. Conclusion: In this diverse cohort of pregnant people with DM, nearly 1 in 5 experienced food insecurity, which may be associated with suboptimal perinatal DM-related health. Although SDoH were not consistently associated with perinatal outcomes, further studies in larger populations may reveal potential areas for interventions.