Article History
Received: 11 July 2019
Accepted: 16 October 2019
First Online: 4 November 2019
Compliance with ethical standards
:
: This study was approved by Ethics Committee of the Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine.
: No financial or nonfinancial benefits have been received or will be received from any party related directly or indirectly to the subject of this article.