1. Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China
2. Department of Clinical Epidemiology, Shengjing Hospital of China Medical University, Shenyang, China
3. Liaoning Women and Children’s Health Hospital, Shenyang, China
4. School of Environmental and Chemical Engineering, Shenyang Ligong University, Shenyang, China
5. Department of Science and Education, Shenyang Women and Children Health Care Centre, Shenyang, China
6. Department of Children’s Health Prevention, Shenyang Women and Children Health Care Centre, Shenyang, China
7. Department of Information Statistics, Shenyang Women and Children Health Care Centre, Shenyang, China