1. Department of Obstetrics and Gynecology, Sumiyoshi Municipal Hospital, Higashikagaya, Sumiyoe, Osaka, Japan.
2. Departments of Obstetrics and Gynecology, Sumiyoe, Osaka, Japan.
3. Pediatric Surgery and Osaka City University Graduate School of Medicine, Asahimachi Abeno, Osaka, Japan.
4. Pediatrics, Osaka City University Graduate School of Medicine, Asahimachi Abeno, Osaka, Japan.