Abstract
INTRODUCTION: The earned income tax credit (EITC), the largest US poverty alleviation program for families with children, provides tax refunds to low-income working families and has been shown to improve perinatal outcomes and reduce racial/ethnic inequities. Variation in when EITC refunds are received during pregnancy allows for a natural experiment of the timing of income receipt on perinatal health. METHODS: National birth certificate data from 2010-2019 and a difference-in-differences study design, were used to examine whether the trimester of EITC disbursal affects likelihood of adverse perinatal outcomes. Analysis was performed in 2025. RESULTS: EITC disbursal during any trimester compared to preconception was associated with higher birthweight, and lower likelihood of preterm birth (PTB, <37 weeks gestational age) and low birthweight (LBW, <2500 grams) with the strongest association in the third trimester (17.81 grams increase in birthweight, 2.16 percentage point decrease in PTB, and 1.19 percentage point decrease in LBW). EITC disbursal during most trimesters of pregnancy was associated with higher prevalence of small-for-gestational-age, gestational diabetes, and gestational hypertension compared to disbursal during preconception. Associations were generally weaker among individuals who were non-White, unmarried, foreign born, and in states without their own EITC policies. CONCLUSIONS: With increasing interest in poverty alleviation during pregnancy to address perinatal health inequities, these results inform timing of interventions.