Funding for this research was provided by:
Postdoctoral Research Foundation of China (2019M661179)
Received: 22 November 2020
Accepted: 8 April 2021
First Online: 28 April 2021
: All procedures were approved by the medical ethics committee of China Medical University (application number: 71774173). The mothers were informed of the project aims and requirements. We obtained written informed consent from the mothers prior to enrollment.
: Not applicable.
: The authors declare no potential conflicts of interest.