About the Authors

Hiroyuki Fujiwara

Affiliation Department of Obstetrics and Gynecology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan

Yuji Takei

Affiliation Department of Obstetrics and Gynecology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan

Yoshiki Ishikawa

Affiliation Department of Health and Social Behavior, School of Public Health, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan

Yasushi Saga

Affiliation Department of Obstetrics and Gynecology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan

Shizuo Machida

Affiliation Department of Obstetrics and Gynecology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan

Akiyo Taneichi

Affiliation Department of Obstetrics and Gynecology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan

Mitsuaki Suzuki

msuzuki@jichi.ac.jp

Affiliation Department of Obstetrics and Gynecology, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi, Japan

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: HF MS. Performed the experiments: HF YS AT SM. Analyzed the data: HF YT YI. Contributed reagents/materials/analysis tools: HF YI. Wrote the manuscript: HF YI MS.