We examine the validity of embedding a simple pre-screening question using naturalistic language in a prescribed prenatal care app to identify those warranting further depression risk assessment. A prospective observational field study examined the validity of an app-embedded pre-screening question to encourage depression screening among a population using a prenatal care app (MHP MyHealthyPregnancyTM) prescribed in a clinical setting and with no incentive for use. Pre-screening validity and subsequent depression screening adherence were contrasted with an in-person screening protocol using established psychometric measures of depression risk. From Nov.2019 – Aug. 2020, 2,910 patients initiated MHP use as part of routine prenatal care. Patients downloading the app were reflective of the demographics of the larger healthcare system patient population, with greater engagement among the 15% of patients identifying as Black or African-American. A voluntary pre-screening question, crafted using a patient-centered design approach and naturalistic language, was completed by 2,149 (74%) of the patients. Twenty-six percent (n=555) responded positively and were prompted to complete the Edinburgh Postnatal Depression Scale (EPDS), of which 97% (n=539) complied. Table I shows the rates of depression risk identified using the app-embedded approach versus a validated in-person combined prescreening (PHQ-2) and full screening (PHQ-9) approach. App-based screening identified a subset of 161 (24%) of patients who were flagged for and completed the EPDS through the app but did not complete a PHQ-9 during in-person care. This study shows the validity of using an app-based screening method to identify those at risk of depression during pregnancy and between routine prenatal care visits. Uptake of app-based depression screening was high and rates of risk identification were comparable to those of in-person care. For digitally-literate patients, app-based screening tools offer a complementary approach to identifying those in need of additional clinical support for psychosocial risks.