Pregnant women and new mothers who have risk factors of child maltreatment are “at high risk for future child maltreatment.” Early detection of them is crucial to prevent it. This community-based, retrospective, cross-sectional, observational study aimed to identify the characteristics of pregnant women, and those in their postpartum period, identified as at-risk cases for child maltreatment. We used data from the municipal pregnancy registration system in City A and analyzed 206 cases identified as “at-risk for child maltreatment” from 1 April 2017 to 31 March 2018. They were categorized into two groups: a pregnancy group (131 cases, 63.6%) and a postpartum group (75 cases, 36.4%). Logistic regression analysis revealed that women who reported having poor relationships with their parents and participated in the interview in their early stages of their pregnancy were less likely to be registered as at-risk cases for child maltreatment after delivery. The results suggest that public health nurses (PHNs) can conduct interviews with pregnant women during the early stages of pregnancy to prevent child maltreatment in community settings. Additionally, to ensure safe delivery and childrearing environments, PHNs need to assess the family support capacity of each registered case and provide assistance to those without parental support.