Conclusion
This study revealed that both >9 h of MSD and excessive gestational BWG had great impact on the incidence of LBW and SGA, and 9 to <10 h of MSD decreased the risk of LBW and SGA in women with appropriate gestational BWG. It is important for care providers to provide the latest data for proper counseling regarding the association between MSD and neonatal birth weight and suggest comprehensive modifications in lifestyles of pregnant women, including sufficient MSD, to prevent LBW and SGA. Furthermore, because JECS is a prospective cohort study, future elucidation of long-term childhood outcomes on the basis of MSD and neonatal birthweight would strengthen the conclusion of this study.
Acknowledgements: The authors are grateful to all the participants of the study and to the Ministry of the Environment, Japan. Members of the JECS Group as of 2020 are: Michihiro Kamijima (principal investigator, Nagoya City University, Nagoya, Japan), Shin Yamazaki (National Institute for Environmental Studies, Tsukuba, Japan), Yukihiro Ohya (National Center for Child Health and Development, Tokyo, Japan), Reiko Kishi (Hokkaido University, Sapporo, Japan), Nobuo Yaegashi (Tohoku University, Sendai, Japan), Koichi Hashimoto (Fukushima Medical University, Fukushima, Japan), Chisato Mori (Chiba University, Chiba, Japan), Shuichi Ito (Yokohama City University, Yokohama, Japan), Zentaro Yamagata (University of Yamanashi, Chuo, Japan), Hidekuni Inadera (University of Toyama, Toyama, Japan), Takeo Nakayama (Kyoto University, Kyoto, Japan), Hiroyasu Iso (Osaka University, Suita, Japan), Masayuki Shima (Hyogo College of Medicine, Nishinomiya, Japan), Youichi Kurozawa (Tottori University, Yonago, Japan), Narufumi Suganuma (Kochi University, Nankoku, Japan), Koichi Kusuhara (University of Occupational and Environmental Health, Kitakyushu, Japan), and Takahiko Katoh (Kumamoto University, Kumamoto, Japan).
Disclosure of interests: The authors report no conflicts of interest.
Contribution to Authorship: T.M. conceptualized and designed the study. T.M., H.K., T.F., S.Y., A.Y., S.M., K.H., H.N., and K.F. contributed to the study design. K.S., A.S., and Y.O. collected the data. T.M. analyzed the data and wrote the manuscript. M.H., S.Y., K.H., K.S., A.S., Y.O., H.N., K.F., and the JECS group reviewed the manuscript and provided critical advice. All authors approved the final manuscript.
Details of Ethical Approval: The JECS protocol was reviewed and approved by the Ministry of the Environment Institutional Review Board on Epidemiological Studies on March 23, 2010 (No. 15000141)22,23 and by the Ethics Committees of all participating institutions. The JECS was conducted in accordance with the principles of the Declaration of Helsinki and other national regulations and guidelines. Written informed consent was obtained from all participating women.
Funding: The Japan Environment and Children’s Study was funded by the Ministry of the Environment, Japan. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the official views of the Ministry of the Environment, Japan.