PROJECT ABSTRACT Reducing rates of maternal morbidity and mortality is a top public health priority in the United States, but little is known about maternal health care utilization and health outcomes in the first few years' postpartum, particularly for women with pregnancy complications. The first two years' postpartum also coincides with the recommended minimum time period between delivery of one infant and start of the subsequent pregnancy?the interpregnancy interval? and the interconception period for women who become pregnant again. In addition, twenty-eight million women (23%) in the US live in nonmetropolitan (rural) areas, and rural-urban disparities in maternal health may exacerbate differences in health care use and outcomes for women with pregnancy complications. Three of the most common (10-20% prevalence) pregnancy conditions are hypertensive disorders of pregnancy, gestational diabetes, and prenatal depression; each is associated with long-term chronic health conditions. Understanding how pregnancy complications are associated with health care use and disease risk during the recommended interpregnancy interval, and if these relations are moderated by rural-urban residency, are critical gaps in the knowledge necessary to improve maternal health in the United States. We propose to use 2006-2020 data from the Maine All Payer Claims Database, a repository containing medical, and pharmacy claim data for Maine residents, which captures approximately 11,000 deliveries per year. We will study maternal health care utilization (emergency department visits, inpatient hospitalizations) and chronic disease diagnoses in the first 24 months' postpartum among women with each of three pregnancy conditions (hypertensive disorders of pregnancy, gestational diabetes, and prenatal depression) in comparison to uncomplicated pregnancies, and evaluate whether associations differ by residence in rural vs. urban areas. For women with pregnancy complications, we will also estimate the impact of living in rural areas on short interpregnancy intervals (<24 months) and the mediating effects of contraception initiation. Our statistical analysis will include descriptive statistics and time-to-event analyses, using inverse probability of censoring weights to account for loss to follow-up and quantitative bias analysis to account for potential misclassification and residual confounding. Graduate students in the public health program will gain hands-on research experience during all stages of this project. Strengths of our project include longitudinal follow-up of women postpartum, regardless of payer, and using population-based data from Maine, which has the highest percentage of residents living in a rural area (60%) in the United States, making it ideal for examining the effects of rural residency. In addition, we are including prenatal depression as one of our three pregnancy conditions, which is increasingly being tied to chronic medical conditions among reproductive age women. The results of our project may advance progress towards lowering maternal morbidity and mortality rates in the US, particularly for women living in rural areas.