About the Authors

Lin Li

Contributed equally to this work with: Lin Li, Chengyan Li

Affiliation Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Guangzhou, China

Chengyan Li

Contributed equally to this work with: Lin Li, Chengyan Li

Affiliations Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Guangzhou, China, Department of Obstetric and Gynecology, Affiliated Hospital of Guangdong Medical College, Zhanjiang, China

Ping Pan

Affiliation Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Guangzhou, China

Xiaoli Chen

Affiliation Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Guangzhou, China

Xiaoke Wu

Affiliation Department of Obstetrics and Gynecology, First Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, China

Ernest Hung Yu Ng

Affiliation Department of Obstetrics and Gynecology, University of Hong Kong, Hong Kong, China

Dongzi Yang

yangdz@mail.sysu.edu.cn

Affiliation Department of Obstetrics and Gynecology, Sun Yat-sen Memorial Hospital, Guangzhou, China

Competing Interests

The authors have declared that no competing interest exist.

Author Contributions

Conceived and designed the experiments: XW EHYN DY. Performed the experiments: LL CL. Analyzed the data: LL PP. Contributed reagents/materials/analysis tools: XC. Wrote the paper: LL.