1. Department of Obstetrics and Gynecology, Qilu Hospital, Shandong University, Jinan, Shandong, China (mainland)
2. Department of Obstetrics and Gynecology, People‘s Hospital, Dezhou, Shandong, China (mainland)
3. Qilu Medical Department, Shandong University, Jinan, Shandong, China (mainland)
4. Laboratory of Birth Regulation and Control Technology of National Health and Family Planning Commission of China, Maternal and Child Health Hospital of Shandong Province, Jinan, Shandong, China (mainland)
5. Department of Pathology, The First Hospital Affiliated with Shandong First Medical University, Jinan, Shandong, China (mainland)