[1] Seirei Hamamatsu Gen Hosp, Maternal & Perinatal Care Ctr, Div Perinatol, Hamamatsu, Shizuoka, Japan
[2] Natl Ctr Child Hlth & Dev, Div Clin Res, Tokyo, Japan
[3] Yamaguchi Univ, Perinatal Care Ctr, Ube, Yamaguchi, Japan
[4] Nagara Med Ctr, Dept Fetal Maternal Med, Gifu, Japan
[5] Natl Ctr Child Hlth & Dev, Dept Maternal Fetal & Neonatal Med, Tokyo, Japan
[6] Miyagi Childrens Hosp, Dept Obstet, Sendai, Miyagi, Japan
[7] Tokyo Metropolitan Komagome Hosp, Dept Pediat, Tokyo, Japan