The California Abundant Birth Project Evaluation: Advancing Birth Equity through Guaranteed Income for Pregnant People - Project Summary/Abstract Pregnancy is a critical period of development: stress during pregnancy can lead to adverse birth and long-term health outcomes, as well as compromise infant development. In the United States, racial inequities in pregnancy and birth outcomes are stark and persistent, signaling the need for novel interventions that address the social determinants of health. The California Abundant Birth Project (CA-ABP) is a guaranteed income program for pregnant populations at elevated risk of preterm birth in five California counties (San Francisco, Alameda, Contra Costa, Riverside, and Los Angeles), funded by the State of California, municipal governments, and philanthropic funding. The CA-ABP program will provide 12-18 months of unconditional, monthly income supplements during pregnancy and postpartum to randomly selected participants, with the goal of curbing financial stress and promoting healthy pregnancy outcomes. The goal of the CA-ABP Evaluation is to use a rigorous, mixed-methods, community-based participatory research approach to determine whether providing guaranteed income to Black pregnant people can advance perinatal health equity through the reduction of adverse pregnancy outcomes and stress, and improvements in maternal mental health and infant development. The proposed project significantly expands the scope of the impact evaluation of CA-ABP by adding three additional survey data collection timepoints (6-weeks postpartum, 6- months postpartum, and 12-months postpartum) and medical records abstraction. The study focuses on the subset of Black-identified participants to determine the impact of income supplementation during pregnancy on: (1) perinatal health, as measured by composite measures of adverse pregnancy outcomes (preterm birth, low birth weight, small-for-gestational age, gestational hypertension, preeclampsia, and gestational diabetes); (2) stress and perinatal mental health (depression and anxiety); and (3) infant development. Eliminating maternal and infant health inequities requires a paradigm shift in research, interventions, and policies that emphasize upstream solutions rather than placing responsibility on affected communities. Understanding the impact of CA-ABP on perinatal health and infant development will provide the foundation for interventions that address stress and economic inequality caused by structural racism. Conducting the evaluation in partnership with the organizations implementing ABP provides a direct pathway to move forward the results for policy change and sustainability.