To determine the association between neighborhood disadvantage and functional brain development of in utero fetuses. We conducted an observational study utilizing Social Vulnerability Index (SVI) scores to assess the impact of neighborhood disadvantage on a prospectively recruited sample of healthy pregnant women from Washington, DC. Utilizing 79 functional MRI scans from 68 healthy pregnancies at a mean gestational age of 33.12 weeks, we characterized overall functional brain network structure using a graph metric approach. We utilized linear mixed effects models to assess the relationship between SVI and gestational age on five graph metrics, adjusting for multiple scans. Exposure to greater neighborhood disadvantage was associated with less well integrated functional brain networks, as observed by longer characteristic path lengths (L) and diminished global efficiency (GE) as well as diminished small world propensity (SWP). Across gestational ages, however, the association between SVI and network integration diminished to a negligible relationship in the third trimester. Conversely, SWP was significant across pregnancy, but the relationship changed such that there was a negative association with SWP earlier in the second trimester that inverted around the transition to the third trimester to a positive association. These data directly connect neighborhood disadvantage and altered functional brain maturation in fetuses. Our results suggest that even prior to birth, proximity to environmental stressors in the wider neighborhood environment are associated with altered brain development.