Prenatal stress exposure may negatively influence the development of the amygdala and hippocampus. Although there is significant income instability during pregnancy, and it can increase stress among pregnant parents, the impact of income instability on brain development is not well understood. The present study examined the association between household income losses during pregnancy and hippocampus and amygdala volumes in early infancy. A total of 63 infants from a prospective longitudinal study of pregnant individuals and their infants completed an MRI during natural sleep. The total number of negative month-to-month earnings shocks (defined as an arc percent change [APC] of -25 or greater) was significantly associated with smaller right hippocampal and right amygdala volumes. This suggests that household income losses during the perinatal period are associated with infant brain structure after birth. These findings provide support for the development of public programs that prioritize financial consistency, especially during sensitive periods like pregnancy.