About the Authors

Junichi Hasegawa

Roles Conceptualization, Data curation, Formal analysis, Investigation, Project administration, Validation, Visualization, Writing – original draft, Writing – review & editing

hasejun@marianna-u.ac.jp

Affiliations Department of Obstetrics and Gynecology, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan, Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan

Tatsuya Arakaki

Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Validation, Visualization, Writing – review & editing

Affiliation Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan

Akihiko Sekizawa

Roles Conceptualization, Data curation, Investigation, Methodology, Supervision, Validation, Visualization, Writing – review & editing

Affiliation Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan

Tomoaki Ikeda

Roles Conceptualization, Supervision, Validation, Writing – review & editing

Affiliation Department of Obstetrics and Gynecology, Mie University School of Medicine, Tsu, Mie, Japan

Isamu Ishiwata

Roles Conceptualization, Supervision, Validation, Writing – review & editing

Affiliation Ishiwata Obstetrics and Gynecology Hospital, Ibaraki, Japan

Katsuyuki Kinoshita

Roles Supervision, Writing – review & editing

Affiliation Seijyo Kinoshita Hospital, Tokyo, Japan

on behalf of department of medical safety, the Japan Association of Obstetricians and Gynecologists (JAOG)

Membership of the Department of Medical Safety, The Japan Association of Obstetricians and Gynecologists (JAOG) is provided in the Acknowledgments.

Competing Interests

The authors have declared that no competing interests exist.