PROJECT SUMMARY Reducing maternal morbidity and mortality is a clinical and public health priority in the United States (US). Substantial research, public health, and clinical efforts focus on reducing morbidity and mortality thought to be due to or aggravated by pregnancy, specifically hemorrhage, hypertension, and venous thromboembolism. However, deaths due to drugs (both illicit and prescription), suicide, and homicide are increasing and may be equally as common among pregnant women and new mothers. It is currently almost impossible to calculate national estimates of pregnancy-associated deaths due to drug use, suicide, and homicide, because the checkbox used to identify these deaths on US death certificates has been shown to undercount cases by 50% or more. We also know little about trends or disparities in these deaths, morbidity due to similar causes that does not result in death, or risk factors for drug use, self-harm, and violence during pregnancy and postpartum. The overall goals of our proposed R01 are to provide the first population-based estimates of incidence, trends, and disparities in mortality and morbidity during pregnancy and the first year postpartum due to drug use, self-harm, and violence, and to ascertain which factors can identify women at high risk of these outcomes in a hospital-based setting. Our first aim is to provide comprehensive national estimates on incidence, trends, and disparities in pregnancy-associated mortality due to drugs, suicide, and homicide in the US between 2007- 2021, adjusted for misclassification arising from errors in the pregnancy checkbox method. Our second aim is to determine incidence, trends, and disparities in pregnancy-associated morbidity due to drugs, self-harm, and violence. Our third aim is to investigate whether hospital or ED service utilization and diagnoses during pregnancy or at delivery can be used to identify women at high risk of future postpartum morbidity and mortality due to drugs, self-harm, or violence. To achieve these aims, we will use a unique set of linked California databases that will allow us to quantify misclassification of pregnancy-associated mortality and apply an innovative bias adjustment to national estimates of pregnancy-associated mortality due to drugs, suicide, and homicide. This dataset will further allow us to estimate pregnancy-associated morbidity due to drug use, self-harm, and violence using a novel linkage approach that follows mothers forward in time from their pregnancy or delivery, and to identify hypothesized antecedent risk factors (?red flags?) for such morbidity and mortality that could create new opportunities for intervention and prevention. The proposed research will extend the current knowledge base in research on maternal morbidity and mortality to encompass non-obstetric causes that are likely of substantial and growing importance. Achieving our aims will change clinical practice by finding ways to identify women at high risk for future morbidity and mortality due to drug use, self-harm, and violence and lay the foundation for future research developing preventive strategies.