Project Abstract Maternal mortality in the US continues to rise, outpacing rates in nearly every other developed country. Over half of women who experience pregnancy-related death do not have risk factors that are identifiable prior to labor. For these women, the cascade of events ending in death or morbidity often begins with labor dysfunction. Current literature on the physiologic determinants of labor dysfunction suggests that lipotoxicity may account for decreased uterine contractile strength and coordination. Lipotoxicity is a system-wide condition occurring when excess free fatty acids are deposited in cellular membranes and non-adipose tissues, causing chronic inflammation and cellular dysfunction in both obese and non-obese women. Black women are 3-4 times more likely to die of pregnancy complications than non-Hispanic white women, and social determinants of health appear to increase their risk of experiencing changes in metabolism during pregnancy. We theorize that alterations in lipid profiles may provide a missing link connecting Black women's pregnancy experiences, health, and labor outcomes. The proposed study will use a systems biology approach to determine how the lipid changes that precede labor dysfunction develop over the course of pregnancy in a cohort of Black women receiving prenatal care in a freestanding birth center (Aim1), and measure the extent to which these lipid changes are influenced by pregnancy health, including maternal behaviors, body composition, social determinants of health, and serum adipose tissue hormones (Aim 2). Finally, we will evaluate the influence of prenatal model of care on pregnancy health and lipid perturbations during pregnancy, comparing the birth center cohort to a cohort of Black women receiving prenatal care in a hospital setting (Aim 3). Recruitment of the birth center cohort will target retention of 150 women who begin prenatal care in first trimester for planned questionnaire and blood collections. Following the completion of labor, detailed chart- review will be performed to identify cases and comparisons for labor dysfunction comparisons. For our final analyses examining the influence of prenatal model of care on lipids and labor outcomes, we will leverage questionnaire and lipidomics data from an existing cohort of 167 Black women with similar levels of perinatal risk to the birth center cohort who received prenatal care in nearby hospital clinics. Differential analysis will then be used to compare lipid features and pregnancy exposures between groups. The proposed research study brings together cutting-edge technology and a multi-disciplinary team with scientific expertise in labor dysfunction, body composition measurement, comprehensive nutritional and physical activity analysis, lipidomics, racial disparities investigations, and systems biology approaches to confront labor dysfunction--one of the most impactful conditions affecting maternal morbidity and mortality. Results obtained f...