About the Authors

Yun-Ping Zhang

ypzhang7090@yahoo.com.cn

Affiliation Department of Gynecology and Obstetrics, Maternal and Child Health Hospital, Haidian District, Beijing, China

Xiao-Hong Liu

Affiliation Department of Gynecology and Obstetrics, Maternal and Child Health Hospital, Haidian District, Beijing, China

Su-Hong Gao

Affiliation Department of Gynecology and Obstetrics, Maternal and Child Health Hospital, Haidian District, Beijing, China

Jia-Mei Wang

Affiliation Department of Gynecology and Obstetrics, Maternal and Child Health Hospital, Haidian District, Beijing, China

Yue-Shan Gu

Affiliation Department of Breast Surgery, Maternal and Child Health Hospital, Tongzhou District, Beijing, China

Jiu-Yue Zhang

Affiliation Department of Anesthesiology, Maternal and Child Health Hospital, Shunyi District, Beijing, China

Xia Zhou

Affiliation Department of Pediatrics, Maternal and Child Health Hospital, Changping District, Beijing, China

Qing-Xia Li

Affiliation Department of Gynecology and Obstetrics, Maternal and Child Health Hospital, Daxing District, Beijing, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: YPZ XHL YSG JYZ XZ QXL. Performed the experiments: XHL SHG XZ QXL. Analyzed the data: YPZ XHL SHG JMW. Contributed reagents/materials/analysis tools: YPZ YSG JYZ. Wrote the paper: SHG JMW XHL YPZ.