Liu, Jingrui
Liu, Xiaowei
Zhao, Shenglong
Zheng, Yuanyuan
Chen, Lu
Wang, Jing
Zhan, Sien
Hu, Siqi
Dong, Ying
Tang, Guodong
Lu, Yifan
Zhai, Yanhong
Cao, Zheng
Article History
Received: 20 April 2020
Accepted: 8 May 2020
First Online: 29 May 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: The study protocol was approved by the Research Ethics Committee of the Beijing Obstetrics and Gynecology Hospital.