1. Maternity and Perinatal Care Center (H.N.) Nagoya University Hospital, Showa-ku, Nagoya 466-8550, Japan;
2. Department of Obstetrics and Gynecology, Nagoya University School of Medicine (A.I., M.O., M.I., A.I., M.O., S.M.), Showa-ku, Nagoya 466-8550, Japan
3. Division of Pathology, Clinical Laboratory (T.N.), Nagoya University Hospital, Showa-ku, Nagoya 466-8550, Japan;