1. Department of Obstetrics and Gynecology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-0054, Japan
2. Department of Obstetrics and Gynecology, Faculty of Medicine, Kagoshima University, Kagoshima 890-8520, Japan
3. Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-0054, Japan