About the Authors

Arihiro Shiozaki

Affiliation Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan

Satoshi Yoneda

Affiliation Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan

Noriko Yoneda

Affiliation Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan

Rika Yonezawa

Affiliation Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan

Takamichi Matsubayashi

Affiliation Toa Pharmaceutical Co., Ltd., Tokyo, Japan

Genichiro Seo

Affiliation Toa Pharmaceutical Co., Ltd., Gunma, Japan

Shigeru Saito

s30saito@med.u-toyama.ac.jp

Affiliation Department of Obstetrics and Gynecology, University of Toyama, Toyama, Japan

Competing Interests

TM and GS are employees of Toa Pharmaceutical Co., Ltd., whose company offered materials for sample collection and collected the samples. There are no patents, products in development or marketed products to declare. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: AS SY NY RY TM GS SS. Performed the experiments: AS SY NY RY TM GS SS. Analyzed the data: AS TM GS SS. Contributed reagents/materials/analysis tools: AS SY NY RY TM GS SS. Contributed to the writing of the manuscript: AS TM GS SS.