Project Summary/Abstract Gestational diabetes mellitus (GDM) is an important contributor to maternal and neonatal morbidity and mortality in pregnancy. Approximately 1 in 8 pregnancies is impacted by GDM worldwide. Despite adverse intergenerational outcomes associated with GDM, this condition is not detected sufficiently early in regular obstetrics practice. Professional societies recommend screening for GDM; however, guidance is inconsistent and late in pregnancy, thus precluding meaningful time to intervene for maternal-offspring benefit. A clinical predictive model that combines clinical risk factors and simple serum biomarkers has shown clinical promise due to its excellent discriminatory ability but has lacked clinical implementation. Therefore, the goal of the proposed research is to: 1) develop an implementation protocol and 2) test the feasibility and acceptability of a first trimester screening protocol for the early detection of GDM. We will conduct a pilot randomized controlled trial among 80 high-risk pregnant women in the first trimester. Participants will be randomized to protocolized early GDM screening with serum biomarkers before 14 weeks gestation or to standard of care (i.e., early screening with additional screening between 24 and 28 weeks of gestation). The proposed K23 award will build on my background in obstetric research focused on diabetes and high-risk pregnancy management. This award will allow me to achieve my training goals: 1) obtain advanced training in statical methods and clinical research methods related to clinical trial design, 2) gain knowledge surrounding mixed methods assessment, 3) develop expertise in executing real- world trials with implementation science methods to test and sustain interventions in obstetric populations, and 4) enhance leadership and academic writing skills to become a successful clinical scientist. Additionally, this award will contribute to my long-term goal of becoming an independent physician-scientist focused on improving the perinatal care of women and their children who develop diabetes during pregnancy. My multidisciplinary mentoring team, and the supportive research environment at the University of Massachusetts Chan Medical School, provide the necessary support for me to achieve my training and research goals. This award will set the stage for a future R01 application to conduct a large scale, multi-site randomized controlled trial assessing the widespread implementation and effectiveness of our early diabetes screening protocol compared with current care standards.