[1] Shenzhen Matern & Child Healthcare Hosp, Dept Obstet, Shenzhen, Guangdong, Peoples R China
[2] Southern Med Univ, Sch Clin Med 1, Shenzhen, Guangdong, Peoples R China
[3] Sun Yat sen Univ, Affiliated Hosp 8, Dept Obstet & Gynecol, Shenzhen, Guangdong, Peoples R China
[4] Tianjin Med Univ, Gen Hosp, Dept Cardiol, 154 Anshan Rd, Tianjin 300052, Peoples R China
[5] Southern Med Univ, Shenzhen Matern & Child Healthcare Hosp, Sch Clin Med 1, Dept Obstet, 2004 Hongli Ave, Shenzhen 518028, Peoples R China