[1] Princess Margaret Hosp, Dept Obstet & Gynecol, Hong Kong, Peoples R China
[2] Tsan Yuk Hosp, Dept Obstet & Gynecol, Prenatal Diagnost Lab, Hong Kong, Peoples R China
[3] Queen Mary Hosp, Hong Kong, Peoples R China
[4] Tuen Mun Hosp, Dept Obstet & Gynecol, Hong Kong, Peoples R China
[5] United Christian Hosp, Dept Obstet & Gynecol, Hong Kong, Peoples R China
[6] Queen Elizabeth Hosp, Dept Obstet & Gynecol, Hong Kong, Peoples R China
[7] Pamela Youde Nethersole Eastern Hosp, Dept Obstet & Gynecol, Hong Kong, Peoples R China