Published on in Vol 9, No 5 (2021): May
Preprints (earlier versions) of this paper are
available at
https://preprints.jmir.org/preprint/22881, first published
.
1 Department of Obstetrics and Gynecology, National Clinical Research Center for Obstetric & Gynecologic Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China