作者单位:School of NursingXuzhou Medical UniversityXuzhou,China[1]Department of Obstetrics and Gynecology, School of MedicineUniversity of North Carolina at Chapel[2]Perelman School of MedicineUniversity of PennsylvaniaPhiladelphia,Pennsylvania[3]School of Nursing, University of North Carolina at Chapel HillChapel Hill,North Carolina[4]