Funding for this research was provided by:
National Natural Science Foundation of China (81873835)
Suzhou Science and Technology Project (SS201702)
Medical Research Project of Jiangsu Public Health Commission (H2017065)
Jiangsu Key Talents for Maternal and Child Health (FRC201715)
Received: 22 June 2020
Accepted: 7 October 2020
First Online: 12 October 2020
Ethics approval and consent to participate
: Informed consent was obtained from each participant. The study design and protocol were reviewed and approved by the ethics committee of Soochow University (Approval No: 201709A183).
: Not applicable.
: The authors declare that they have no competing interests.