[Gao, H; Gao, Hong; Tan, Lingling] Univ South China, Affiliated Hosp 2, Hengyang Med Sch, Nursing Dept, Hengyang, Peoples R China.
[Gao, H; Gao, Hong] Ottawa Hosp, Res Inst, Ottawa, ON, Canada.
[Chen, Yahui; Liu, Qiao] Univ South China, Sch Nursing, Hengyang, Peoples R China.
[Li, Genlin; Wang, Xiaolan] Univ South China, Affiliated Hosp 1, Ctr Combinat Obstet & Gynecol & Reprod Med, Hengyang Med Sch, Hengyang, Peoples R China.
[Li, Ting] Univ South China, Affiliated Hosp 2, Hengyang Med Sch, Dept Obstet, Hengyang, Peoples R China.