BACKGROUND: Postpartum mental health problems are a major public health issue; however, studies on the mental health status of mothers and its influencing factors between 8 weeks and 1 year postpartum are scarce. Furthermore, it would be necessary to examine the factors influencing mothers' mental health in order to evaluate their physiological adaptations to the nursing environment. METHODS: We examined the mental health status of postpartum women and the factors influencing poor mental health at 4 months after delivery. A cross-sectional study of 584 postpartum women was conducted. Information on mental health status, delivery, and other factors was collected using a self-administered questionnaire. Women were asked about their age, height, weight, gestational or marital status, whether they were eating regular meals, appetite, frequency of going out, financial difficulty, stressful life events, and history of depression. The Japanese version of the 12-item General Health Questionnaire (GHQ-12) was used to identify potential poor mental health status. Participants with GHQ-12 scores of ?4 were classified as the high GHQ-12 score group (poor mental health status) and participants with GHQ-12 scores of ?3 were classified as the low GHQ-12 score group (good mental health status). RESULTS: Forty-five women (7.7%) were classified as having high GHQ-12 scores. Multiple logistic regression analysis revealed that older age, not eating meals regularly, and history of depression were significantly associated with poor mental health. Financial difficulty had a borderline association with poor mental health in this model. CONCLUSIONS: These risk factors might help practitioners identify women at high risk of poor mental health after delivery.;開始ページ : 32;元資料の権利情報 : © 2014 Yamamoto et al.; licensee BioMed Central Ltd.;元資料の権利情報 : This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.