Funding for this research was provided by:
Japan Society for the Promotion of Science (17K16857, 18K16774, 15K10679, no. 16K11093)
Oita Society of Obstetrics and Gynecology
Received: 3 January 2020
Accepted: 13 April 2020
First Online: 16 April 2020
Ethics approval and consent to participate
: The present study was approved by the Institutional Review Board (IRB) of the Faculty of Medicine, Oita University (registration number: P-16-01). Written informed consent was obtained from all the patients.
: Not applicable.
: There are no conflicts of interest to declare.