Heung Yeol Kim1, Ari Kim2. 1. Department of Obstetrics and Gynecology, College of Medicine, Kosin University, Busan, South Korea. Electronic address: hykyale@yahoo.com. 2. Department of Obstetrics and Gynecology, Institute of Wonkwang Medical Science, College of Medicine, Wonkwang University, Iksan, South Korea.