[1] Dokkyo Med Univ, Integrated Res Fac Adv Med Sci, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
[2] Yokohama City Univ, Yokohama City Univ Hosp, Dept Obstet & Gynecol, Grad Sch Med,Kanazawa Ku, 3-9 Fukuura, Yokohama, Kanagawa 2360004, Japan
[3] Dokkyo Med Univ, Sch Med, Dept Publ Hlth, 880 Kitakobayashi, Mibu, Tochigi 3210293, Japan
[4] Yokohama City Univ, Perinatal Ctr Matern & Neonates, Med Ctr, Kanazawa Ku, 3-9 Fukuura, Yokohama, Kanagawa 2360004, Japan
[5] Hokkaido Univ, Dept Obstet & Gynecol, Grad Sch Med, Kita Ku, N15W7, Sapporo, Hokkaido 0608648, Japan
[6] Yokohama City Univ Med, Dept Psychiat, Kanazawa Ku, 3-9 Fukuura, Yokohama, Kanagawa 2360004, Japan
[7] Mie Univ, Obstet & Gynecol, Grad Sch Med, 2-174 Edobashi, Tsu, Mie 5148507, Japan
[8] Osaka Univ, Dept Obstet & Gynecol, Grad Sch Med, 2-2 Yamadaoka, Suita, Osaka 5650871, Japan
[9] Kobe Univ, Dept Obstet & Gynecol, Grad Sch Med, Chuo Ku, 7-5-1 Kusunoki Cho, Kobe, Hyogo 6500017, Japan