[1] Int Univ Hlth & Welf, Mita Hosp, Prevent Med Ctr, Minato Ku, 1-4-3 Mita, Tokyo, Japan
[2] Saku Cent Hosp, Adv Care Ctr, Nagano Prefectural Federat Agr Cooperat Hlth & We, Nagano, Japan
[3] Kyorin Univ, Dept Obstet & Gynecol, Fac Med, Tokyo, Japan
[4] Keio Univ, Sch Med, Dept Obstet & Gynecol, Tokyo, Japan