1. Department of Obstetrics and Gynecology; Fuzhou General Hospital, Fujian Medical University; Fuzhou Fujian China
2. Central Station of Environmental Monitoring of Fujian Province; Fuzhou Fujian China
3. Dongfang Affiliated Hospital of Xiamen University; Xiamen Fujian China
4. China International Science & Technology Cooperation Base for Environmental Factors on Early Development; Fuzhou Fujian China
5. Department of Obstetrics and Gynecology; Fujian Maternity and Children Health Hospital, Teaching Hospital of Fujian Medical University; Fuzhou Fujian China
6. Fuzhou Institute of Product Quality Inspection; Fuzhou Fujian China
7. Division of Environmental Health Sciences; College of Public Health, The Ohio State University; Columbus Ohio 43210-1240 USA