Reductions in biopsychosocial risks for pregnant Latinas and their infants: the Mastery Lifestyle Intervention - Project Summary/Abstract Pregnant Mexican-American women (the largest subgroup of Hispanic women), hereafter referred to as Latinas, are at increasing risk for psychological distress which leads to adverse birth outcomes such as preterm birth (PTB, gestational age < 37 weeks) and low birthweight (LBW, <2500 grams). Our prior research, using a psychoneuroimmunology (PNI) framework, has identified psychological risk factors (depressive symptoms, anxiety, stress, coping) and neuroendocrine risk factors (high Corticotropin Releasing Hormone [CRH], lower progesterone, higher estriol) at 22-24 weeks gestation as strong predictors of PTB in Latina women. New interventions targeting these risk factors need to be identified and rigorously tested. To address the gaps related to interventions for Latinas, we have developed and successfully pilot tested the Mastery Lifestyle Intervention (MLI): a culturally-relevant, manualized psychosocial group intervention that integrates two evidence-based behavioral therapies – Acceptance and Commitment Therapy (ACT) and Problem-Solving Therapy (PST). The MLI is a 6-week program designed to be integrated into regular prenatal care to facilitate more comprehensive care delivered by a nurse practitioner (NP) or certified nurse midwife (CNM). We propose the following aims for a randomized controlled trial: Primary Aim 1: Determine the efficacy of the MLI in pregnant Latina women to decrease depressive symptoms, anxiety, perceived and acculturative stress, and to improve coping, versus usual care (UC), from baseline (14-20 weeks gestation) to end-of-treatment (20-26 weeks gestation) and at a 6 week follow-up (26-32 weeks gestation), with acculturation and psychological flexibility as mediators. Exploratory Aim 2: Explore the effect of the MLI on neuroendocrine risk factors of PTB (CRH, progesterone, and estriol) versus UC from baseline to end-of treatment. Exploratory Aim 3: Explore the effect of the MLI on infant birth outcomes (gestational age, birthweight, NICU admission). Analyses for each hypothesis will rely on generalized linear mixed modeling (GLMM) with random effects for participant and time as necessary to account for correlated observations. Longitudinal analyses will model each outcome as a function of treatment group, time, and the interaction between treatment group and time. We will also use SEM to analyze for mediators. We expect the MLI will provide a greatly needed, novel, feasible, and effective nonpharmacological program added to the toolbox of treatments assisting providers to improve health during pregnancy. Embedded into prenatal care, it targets psychological distress among pregnant Latina women, an underserved population. It may substantially reduce the risks for poor birth outcomes, thus reducing devastating and long-term effects for both mother and infant.