1. Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Maternal and Child Health Care Hospital of Shandong Province Affiliated to Qingdao University
2. The Second Hospital, Cheeloo College of Medicine, Shandong University
3. Jinan Environmental Monitoring Center of Shandong Province
4. School of Public Health, Weifang Medical University
5. Department of Obstetrics and Gynecology, Shandong Provincial Hospital Affiliated to Shandong First Medical University