The aim of this paper is to describe the technique of "Ibaraki Cohort Study" and clarify the future issues concerning the conduct of the survey. The research program of Ritsumeikan Global Innovation Research Organization has conducted a follow-up survey that continuously tracked prenatal and postnatal women since 2017. The participants of this study live in Ibaraki city, so that this study is called “Ibaraki Cohort Study”. The purpose of the study is to clarity the physical and mental burdens of participants and their changes, the social situations of the participants, and how their situations affect the development of their children. The Ibaraki Cohort Study, which is based on questionnaire surveys, is designed to link interview surveys, saliva surveys, and behavioral observations. In order to do the survey, we have set up an administrative office to manage participants list, send email invitations to each participant at appropriate timing, and considered devises for maintaining participants. In this paper, we discussed the whole design, feasibility, subject maintenance methods, data collection and management of Ibaraki cohort study. As a result of organizing these techniques, future issues related to output of results and the operation of the secretariat were mentioned.

Ethical considerations are essential in human research. Research teams need a wide range of considerations, such as informed consent, protection of personal information, and responsibility to a collaborator's health condition. However, it is difficult to expect or plan all cases, especially in a large-scale cohort surveys. In addition, as a research team, there is a limitation to support and information provision to research subjects. This report describes the content and ideas of ethical considerations that the research team has discussed in the Ibaraki cohort study. Specifically, this report described the characteristics of ethical considerations in large-scale cohort surveys in 4 points; 1) informed consent, 2) personal information protection, 3) consideration in interview surveys, saliva survey and behavior observation, 4) feedback on survey results. How we deal with the problem of reported depression is described in 4 points; 1) outline, 2) feedback on results of depression, 3) cooperation with Ibaraki city, 4) making manual. Finally, we discussed the ethical issues that arise in the process of carrying out the research.