Recent evidence on perceived stress during the COVID-19 pandemic shows that birthing people experienced stress from pandemic-related stressors. While psychosocial stress is a significant predictor of adverse birth outcomes, social support can reduce stress levels during pregnancy. This study examined social support moderation of relationships between COVID-19-related stressors and perceived stress during pregnancy. The analysis included data from publicly insured pregnant participants who were enrolled in a randomized control trial of two enhanced prenatal care models in Fresno, California, and completed a third-trimester questionnaire between April and August 2020 (n = 77). Multivariate linear regression was used to estimate the associations between perceived stress and COVID-19-related stressors and social support moderation. COVID-19-related stressors related to childcare and tension at home remained significantly associated with perceived stress adjusting for sociodemographic characteristics and other COVID-19-related stressors. Social support moderated the relationship between perceived stress and loss of childcare (β = 2.4, 95 percent CI = 0.5-4.3, p = .014). Overall, social support moderated the association between COVID-19 stressors and perceived stress. While social support is commonly conceptualized as protective, the finding of greater stress around childcare among individuals reporting greater social support suggests complexity for leveraging these support networks during the pandemic.