The transition to parenthood has long been viewed as a period of change in new parents' romantic relationships. However, this research has largely focused on changes in relationship quality, generally overlooking changes in relationship status (e.g., ending or entering a relationship during this period). To address this gap, we explored patterns and predictors of relationship dissolution and relationship formation during the early postpartum period among a sample of first-time Black mothers. A community sample of mothers living with low incomes (N = 212; 10% married; 85% enrolled in Medicaid) reported on their relationship status and other characteristics at 1, 8, and 16 weeks postpartum. Among mothers who were in a relationship at 1 week postpartum (N = 126), 20% of these relationships ended by Week 8 or 16. Mothers whose relationships ended reported lower relationship functioning at Week 1 than mothers whose relationships remained intact. Among mothers who were single at 1 week postpartum (N = 86), over 50% subsequently reported being in a relationship at Week 8 or 16. Mothers who started relationships reported lower overall social support at Week 1 relative to mothers who remained single. Together, these findings indicate that changes in relationship status during the early postpartum period were common and provide initial insights into factors characterizing mothers who experienced relationship transitions. Future work would benefit from considering changes in relationship status as well as other relational changes during the transition to parenthood to reflect a wider range of experiences among new parents.