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