BACKGROUND: Maternal mental health conditions are associated with unmet Social Determinants of Health (SDOH) needs and can impede access to mental health and substance use disorder (SUD) treatment, leading to poor maternal and newborn health outcomes. A text/phone-based maternal mental health screening and referral to treatment intervention, Listening to Women and Pregnant and Postpartum People (LTWP), has demonstrated improved rates of screening, screening positive for mental health concerns, referral to and attendance of mental health and SUD treatment compared to usual care (i.e., in-person screening and referral). It is unknown, however, if LTWP improves identification of individuals with unmet SDOH needs. This study examines rates of screening, screening positive, referral and attendance to mental health treatment among those with unmet SDOH needs compared to those not experiencing unmet SDOH needs. METHODS: This secondary analysis includes participants randomized to LTWP and endorsing one or more unmet SDOH need (n = 78) or no unmet SDOH need (n = 103) measured by the Accountable Health Communities Health-Related Social Needs Screening Tool via an online survey. Differences in groups' rates of completing a screening, screening positive, being referred to treatment and attending treatment were compared between groups using chi-square tests and relative risk as a measure of association. Adjustments for missing SDOH data via multiple imputations were performed for analysis of the full cohort of LTWP endorsing at least one unmet SDOH need (n = 106) or no unmet SDOH need (n = 118). RESULTS: Among LTWP participants, 43.0% (78/181) reported at least one unmet SDOH need with financial strain (55.1% (43/78)), disabilities (34.6% (27/78)), and food insecurity (33.3% (26/78)) being the most frequently reported SDOH. On average, participants with SDOH needs were significantly younger (29.0 vs. 32.0 years), more likely to self-identify as non-Hispanic Black (42.3% vs 13.6%), and report a lower household annual income (33.3% vs 1.9% under 5,000), compared to those without SDOH needs. Those with SDOH needs were more likely to screen positive for mental health concerns (RR: 1.59
95% CI: 1.21-2.09), be referred to (RR: 2.97
95% CI: 1.36-6.48), and attend mental health treatment (RR: 2.64
95% CI 1.04-2.73) compared to those without SDOH needs. CONCLUSIONS: The LTWP intervention, a simple text- and phone-based screening approach with referral to care as needed, shows promise in increasing access to mental health and substance use treatment for individuals with unmet social determinants of health needs and demonstrates potential to enhance screening, identification, and treatment attendance rates for perinatal mental health disorders and substance use disorders compared to traditional in-person systems.