[1] Southern Med Univ, Foshan Inst Fetal Med, Affiliated Maternal & Child Hlth Hosp Foshan, Foshan 528000, Guangdong, Peoples R China
[2] Southern Med Univ, Dept Obstet, Affiliated Maternal & Child Hlth Hosp Foshan, Foshan 528000, Guangdong, Peoples R China
[3] Anhui Med Univ, Sch Publ Hlth, Dept Epidemiol & Biostat, Hefei 230032, Anhui, Peoples R China
[4] Zhejiang Univ, Dept Lib, Affiliated Hosp 1, Coll Med, Hangzhou 310003, Zhejiang, Peoples R China
[5] Anhui Med Univ, Sch Publ Hlth, Dept Maternal Child & Adolescent Hlth, Hefei 230032, Anhui, Peoples R China
[6] Anhui Univ Chinese Med, Sch Integrated Tradit & Western Med, Hefei 230038, Anhui, Peoples R China