Background: There are many reports in the mass media and scientific literature about child abuse caused by parents. Medical practitioners also are concerned about child abuse and need to grapple with the prevention and early detection of child abuse when working in medical facilities. Aim: The aim of this descriptive study was to explore the relationship between maternal and child factors contributing to child abuse. Methods: A sample of 50 multiparas (mothers with more than 1 child) in a 48-bed postpartum (...) hospital unit in Okinawa prefecture were asked to fill out an anonymous questionnaire regarding the relationship between mothers and their first child in September, 2007. The questionnaire contained 30 items of physical punishment that are quoted from “The Handbook of Correspondence to Child Abuse” (Ministry of Health, Labor and welfare in Japan), 24 items relating to maternal factors and 22 items to child factors, plus items related to mothers’ satisfaction with the health guidance given in the hospital. Data were analyzed using JMP (ver. 14.2; SAS Institute Inc., Cary, NC, U.S.). The significance level was set at 0.05. Results: Forty-one (82%) questionnaires were analyzed. Of the 41 valid responses, 19 mothers reported abusing their children. Child factors contributing to the abuse included the first child’s regression to infantile behavior, bullying younger brothers or sisters and being rough and violent to their friends. The significant maternal factor leading to abuse was the belief that mothers were irritated by their child. Conclusion: A first child’s developmental difficulties had a significant relationship with the harsh punishment by their mothers. The mothers need to understand their child’s developmental behavior and provide a favorable environment for nurturing young children. (shrink)