[1] Guangzhou Med Univ, Dept Tradit Chinese Med, Affiliated Hosp 1, Guangzhou, Guangdong, Peoples R China
[2] Univ Hong Kong, Hong Kong Special Adm Reg, Dept Obstet & Gynecol, Hong Kong, Hong Kong, Peoples R China
[3] Karolinska Inst, Dept Physiol & Pharmacol, Stockholm, Sweden
[4] Xuzhou Matern & Child Hlth Hosp, Dept Gynecol, Xuzhou, Jiangsu, Peoples R China
[5] Chinese Clin Trial Registry, Beijing, Peoples R China