[1] St Marianna Univ, Dept Obstet & Gynecol, Sch Med, Kawasaki, Kanagawa, Japan
[2] Kindai Univ, Nara Hosp, Dept Diagnost Pathol, Fac Med, Ikoma, Japan
[3] Osaka Univ, Dept Legal Med, Grad Sch Med, Osaka, Japan
[4] Osaka Med Ctr & Res Inst Maternal & Child Hlth, Dept Pathol, Izumi Ku, Osaka, Japan
[5] Hamamatsu Univ Sch Med, Dept Obstet & Gynecol, Hamamatsu, Shizuoka, Japan
[6] Mie Univ, Dept Obstet & Gynecol, Sch Med, Tsu, Mie, Japan
[7] Sakakibara Heart Inst, Dept Obstet & Gynecol, Tokyo, Japan
[8] Toho Univ, Dept Obstet & Gynecol, Sch Med, Tokyo, Japan
[9] Seirei Hamamatsu Gen Hosp, Div Perinatol, Maternal & Perinatal Care Ctr, Hamamatsu, Shizuoka, Japan
[10] Showa Univ, Dept Obstet & Gynecol, Sch Med, Tokyo, Japan
[11] Ishiwata Obstet & Gynecol Hosp, Ibaraki, Japan