Article History
Received: 13 January 2018
Accepted: 29 June 2018
First Online: 3 July 2018
Compliance with ethical standards
:
: Our study protocol was approved by the Medical Ethics Committee of the International Peace Maternity and Child Health Hospital (IPMCH) of China Welfare Institute (IRB reference number: GKLW 2017-51). All patients admitted at our center had consented to the anonymous use of their medical data for scientific research, publication and/or quality assessment, and informed consents were previously signed at the beginning of their treatments. And because the study was designed to retrospectively analyze the data of patients who had finished their treatments, further consent was not necessary.
: The authors declare that they have no conflict of interest.