Received: 8 January 2021
Accepted: 31 March 2021
First Online: 25 May 2021
: All methods were performed in accordance with the relevant guidelines and regulations. Ethics approval was obtained from the ethics committee of the Shenzhen Maternity and Child Health Hospital. A hard copy of the consent form was provided to each study participant and informed consent was obtained from all participants.
: The authors declare that they have no competing interests.