PROJECT SUMMARY At odds with common assumptions — and hope, pregnancy ends in preterm birth (PTB) for approximately 1 in 10 women. Yearly PTB affects 15 million infants worldwide and 386,580 in the United States. PTB is the leading cause of global, and U.S., neonatal mortality and morbidity and is associated with future risk for poor physical (higher blood pressure, chronic kidney disease, wheeze/asthma) and mental (ADHD, IQ decrements) health. Maternal health is not spared: women who deliver preterm are at an increased risk for depression, hypertension, cardiovascular and renal disease later in life. In the U.S., the racial and ethnic disparities in PTB rates are dramatic and independent of socio-economic status (SES): overall, 14.12% for Non-Hispanic Black compared to 9.09% for Non-Hispanic White women. Psychosocial stress and childhood trauma each are associated with risk for PTB. PTB has an intergenerational impact: mothers born preterm are more likely to give birth preterm, especially amongst Black women. Literature proposing psychosocial and physiologic pathways between maternal stress and PTB demonstrate significant differences in self-reported and biologic markers of stress between non-Hispanic Black and White women. Racial and ethnic differences have also been reported in dietary behaviors in response to acute stress and economic adversity from food insecurity. We aim to identify nutritional profiles of pregnant women with food insecurity and psychosocial stress, determine racial and ethnic differences in nutritional profiles by food insecurity and psychosocial stress experiences, and evaluate whether nutritional profiles affect the pathway by which food- and psychosocial- related stress contributes to increased risk for PTB among racial and ethnic minoritized women. In a sample of post-attrition n=175 pregnant women we will test the following two aims: Aim 1: To determine whether there are unique nutritional profiles (self-reported maternal dietary quality and serum 25-hydroxy Vitamin D level) of pregnant women with food insecurity and psychosocial stress (anxiety, depression, perceived stress) that differ by race and ethnicity. Aim 2: To evaluate if maternal prenatal nutrition mediates the association between food- and psychosocial-related stress and earlier gestational age (GA) at birth and if this mediation is moderated by race and ethnicity. This new conceptual framing of PTB that incorporates dietary intake and quality is important to identify new biologic and behavioral mechanisms for PTB risk that will inform future interventions that can reduce PTB and dietary disparities.