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Background: Psychosocial stress during pregnancy has been associated with a number of adverse birth outcomes, including preterm birth. However, we have a limited understanding of the biologic pathways that might link stress to adverse outcomes. Corticotrophin Releasing Hormone (CRH) may represent one possible mechanism, as elevated levels of CRH have been associated with preterm birth. The purpose of this study was to examine the relationships between maternal self-reported psychosocial stress and CRH during pregnancy. We hypothesized that women who experienced psychosocial stress would have elevated levels of CRH. Methods: Women were enrolled in the Chemicals in Our Bodies-2 cohort (N=496), a demographically diverse cohort of pregnant women in San Francisco. CRH (pg/mL) was measured in plasma obtained at the 2^nd trimester visit. Psychosocial stress was assessed via self-reported questionnaire at the 2^nd trimester and included dichotomous measures of neighborhood quality, stressful life events, caregiving, discrimination, financial strain, job strain, food insecurity, unplanned pregnancy, perceived stress, depression, and perceived community status. Linear regression was used to examine associations between psychosocial stressors and CRH. Results: Experiencing >2 stressful life events was associated with elevated levels of CRH after adjusting for gestational age at visit, maternal race/ethnicity, maternal education, and marital status (β=0.16, 95% confidence interval [CI]=0.02, 0.31). Women who experienced financial strain (β=0.13, 95% CI=-0.10, 0.36), caregiving for an ill family member (β=0.13, 95% CI=-0.06, 0.32), or who had elevated levels of perceived stress (β=0.20, 95% CI=-0.20, 0.41) also had moderately increased CRH levels. No associations were observed between other psychosocial stressor and CRH levels. Conclusions: We observed a positive association between stressful life events and elevated CRH levels in our study population. Future research should explore the combined effects of psychosocial stress and chemicals on birth outcomes and examine CRH as a mediator of the psychosocial stress and birth outcomes relationships.