[1] Nanjing Med Univ, Obstet & Gynecol Hosp, Nanjing, Jiangsu, Peoples R China
[2] Childrens Hosp Philadelphia, Cardiac Ctr, Fetal Heart Program, 3401 Civ Ctr Blvd, Philadelphia, PA 19104 USA
[3] Univ Penn, Perelman Sch Med, Dept Pediat, Div Cardiol, Philadelphia, PA USA