1. Department of Obstetrics and Gynecology Shengjing Hospital, China Medical University Shenyang China
2. Key Laboratory of Maternal‐Fetal Medicine of Liaoning province China Medical University Shenyang China
3. Key Laboratory of Obstetrics and Gynecology of Higher Education of Liaoning Province China Medical University ShenyangChina
4. Research Center of China Medical University Birth Cohort China Medical University Shenyang China