1. Department of Public Health, Juntendo University Graduate School of Medicine, Tokyo 113-0033, Japan
2. Department of Obstetrics and Gynaecology, Juntendo University Faculty of Medicine, Tokyo 113-8421, Japan
3. Centre for Reproductive Medicine and Endoscopy, Sugiyama Clinic Marunouchi, Tokyo 100-0065, Japan
4. Department of Hygiene, Public Health, and Preventive Medicine, Showa University, Tokyo 142-8555, Japan
5. Saint Mother Hospital Infertility Clinic, Fukuoka 807-0825, Japan
6. Centre for Reproductive Medicine and Implantation Research, Sugiyama Clinic Shinjuku, Tokyo 116-0023, Japan
7. Takasaki ART Clinic, Gunma 370-0831, Japan