PROJECT SUMMARY Research into effective strategies to reduce unintended pregnancy and short interval births, and to mitigate associated adverse maternal and neonatal health outcomes, has been hampered by poor conceptualization and measurement of pregnancy intentions. Until recently, no validated psychometric measures had been available to prospectively capture the range and complexity of feelings many women have about pregnancy, including ambivalence and uncertainty. Reliance on simplistic measures and retrospective data have left serious scientific gaps in our understanding of the causes, and health consequences, of unintended pregnancy and short interpregnancy intervals (IPIs). Scholars have expressed an urgent need for improved measures and longitudinal study designs, citing their importance to rigorous investigations of the role of pregnancy intentions on the causal pathway to unintended pregnancy, short IPIs, and adverse health outcomes. This proposal addresses these critical scientific and measurement gaps using longitudinal data from population-based surveys, fielded to over 12,000 women, aged 18-44, across nine US states. These surveys include the Desire to Avoid Pregnancy (DAP) scale, a novel instrument developed by our team using cutting-edge, rigorous psychometric methods. The instrument reconceptualizes “intentions” as “preferences” and captures the diversity of considerations and feelings women have about a potential future pregnancy. Using three years of data, we will examine the predictive relationships between DAP scores, contraceptive use, incident pregnancy, and birth outcomes. We will use structural equation models to investigate the extent to which DAP scores mediate relationships between the personal and social contexts of women’s lives and pregnancy and birth outcomes, addressing confounding that has hindered prior investigations. Critically, analyses will for the first time apply prospective pregnancy preference data to investigate whether the elevated risk of negative maternal and birth outcomes from short IPIs results from physiologic mechanisms, or the contexts in which these frequently unintended pregnancies occur. We will then capitalize on the DAP’s strengths to develop novel measurement tools that expand its utility. First, we will use item response theory (IRT) to develop a shorter DAP version that maintains construct validity, facilitating the integration of rigorous, person-centered measures into future research, surveillance, and clinical care. Then, we will use IRT to establish evidence-based thresholds on the scale, defining standardized groupings of pre-pregnancy preferences (e.g., “undesired” or “less preferred”), and addressing the urgent need for alternative measures to “unintended pregnancy” that capture if women attain their reproductive preferences. A better understanding of how pregnancy preferences are formed, and how unintended pregnancy contributes to adverse maternal and neonatal outcomes – as well ...