Corresponding author:
Eiji Shibata
Department of Obstetrics and Gynecology, University of Occupational and Environmental health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu-city, Fukuoka 807-8555, Japan
Telephone No.: +81-93-603-1611
Fax No.: +81-93-691-9337
Email address: age-s@med.uoeh-u.ac.jp