[1] Iizuka Hosp, Dept Obstet & Gynecol, Iizuka, Fukuoka, Japan
[2] Fukuoka Univ Hosp, Ctr Maternal Fetal & Neonatal Med, Fukuoka 8140180, Japan
[3] Yamaguchi Red Cross Hosp, Dept Obstet & Gynecol, Yamaguchi, Japan
[4] Kitakyushu Municipal Hosp, Dept Obstet & Gynecol, Fukuoka, Japan
[5] Natl Hosp Org, Kyushu Med Ctr, Clin Res Inst, Dept Obstet & Gynecol, Fukuoka, Japan
[6] Japan Community Hlth Care Org, Kyushu Hosp, Dept Obstet & Gynecol, Fukuoka, Japan
[7] Oita Prefectural Hosp, Dept Obstet & Gynecol, Oita, Japan
[8] Fukuoka Univ, Fac Med, Dept Obstet & Gynecol, Fukuoka 81401, Japan