1 Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Maternal and Child Health Care Hospital of Shandong Province, Shandong University, Jinan 250001, China; Department of Occupational and Environmental Hygiene, School of Public Health, Zhengzhou University, Zhengzhou 450001, China.
2 Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Maternal and Child Health Care Hospital of Shandong Province, Shandong University, Jinan 250001, China.
3 School of Public Health, Xinxiang Medical University, Xinxiang 453003, China.
4 Department of Occupational and Environmental Hygiene, School of Public Health and Management, Weifang Medical University, Weifang 261042, China.
5 Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Maternal and Child Health Care Hospital of Shandong Province, Shandong University, Jinan 250001, China. Electronic address: zhanglin8901@163.com.