Identifying age 26 as a threshold in psychosocial risks associated with child maltreatment among first-time mothers: a cross-sectional study in Japan

Background Early pregnancy is associated with increased psychosocial vulnerability, which has been linked to factors associated with child maltreatment. However, previous research has predominantly focused on teenagers, and little is known about whether first-time mothers in their early-to-mid twenties also exhibit elevated psychosocial risks. This observational cross-sectional study aimed to determine whether psychosocial risk factors associated with child maltreatment are more prevalent among first-time mothers aged 17–25 years in Japan, compared with those aged 26 years and older. Methods Routine administrative data were collected in July 2022 from 429 first-time pregnant women aged 17–43 years who submitted pregnancy notifications to their local municipal office in four municipalities in the Tokyo metropolitan area, Japan. A cumulative psychosocial risk score was calculated by summing six binary indicators: being unmarried, living alone, low household income, low educational attainment, poor mental well-being, and low perceived social support. A segmented regression analysis was used to identify the age at which the association with cumulative psychosocial risk changed. Results The association between maternal age and psychosocial risk factors associated with child maltreatment was most prominent up to age 26. A data-driven breakpoint at 25.9 years suggested that younger age was associated with greater psychosocial risk. Younger mothers (ages 17–25, n = 158) were more likely to be unmarried, live alone, have a low socioeconomic status, and have lower educational attainment compared with older mothers (ages 26–43, n = 271; p < 0.005). Conclusion First-time pregnant women aged 17–25 years in Japan exhibited higher levels of psychosocial risk factors associated with child maltreatment compared with those aged 26 years and older. These findings suggest that, in addition to teenagers, women in their early-to-mid twenties should be recognized as a priority group for early preventive support within maternal and child health systems. Integrating age-informed approaches into public maternal health policy and antenatal care may help strengthen early prevention child maltreatment.