Funding for this research was provided by:
Korean society of Maternal Fetal Medicine Research Fund (KSMFM-2019-001)
Received: 4 May 2020
Accepted: 10 November 2020
First Online: 23 November 2020
Ethics approval and consent to participate
: The institutional review board of Korea University Guro Hospital approved the collection and use of clinical information for research purposes (No. 2020GR0012; Approval date, January 9, 2020). This study is in compliance with the 2013 Helsinki World Medical Association Declaration.
: Not applicable.
: The authors declare that they have no competing interests.