1,981
Participants
Start Date
September 8, 2018
Primary Completion Date
September 30, 2019
Study Completion Date
December 31, 2019
Peking University People's Hospital, Beijing
Haidian women and children's hospital of beijing, Beijing
Shunyi women and children's hospital of Beijing Children's Hospital, Beijing
Fourth Hospital of Heibei Medical Hospital, Shijiazhuang
Peking University
OTHER