Updates are available Correction dated 2020-06-30

Article History

Received: 28 November 2018

Accepted: 31 July 2019

First Online: 3 February 2020

Change Date: 30 June 2020

Change Type: Correction

Change Details: Affiliation 1 was incorrect in the original article and should have read: ���Department of Obstetrics, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.���

Compliance with Ethical Standards

: The utilization of clinical samples followed the guidelines of the Ethics Committee of the Beijing Obstetrics and Gynecology Hospital; all clinical samples were collected from the Beijing Obstetrics and Gynecology Hospital. We obtained written informed consent for donating placentas from the pregnant women involved.

: The authors declare that they have no conflicts of interest.