1. Department of Reproductive Medicine, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China;
2. Key Laboratory of Reproductive Medicine of Guangdong Province, Guangzhou, Guangdong, China;
3. Key Laboratory for Major Obstetric Diseases of Guangdong Province, Guangzhou, Guangdong, China;
4. Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, Guangzhou, Guangdong, China