1. Obstetrics & Gynecology Department, School of Nursing, Sun Yat-sen University, Guangzhou, China
2. Nursing Department, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
3. School of Nursing, Sun Yat-sen University, Guangzhou, China
4. Obstetrics & Gynecology Department, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China