1. Department of Obstetrics and Gynecology, Tokyo Medical and Dental University, Yushima, Bunkyo, Tokyo, Japan
2. Department of Women’s Health, Tokyo Medical and Dental University, Yushima, Bunkyo, Tokyo, Japan
3. Department of Obstetrics and Gynecology, Tokyo Metropolitan Ohtsuka Hospital, Minami-Otsuka, Toshima, Tokyo, Japan
4. Department of Biostatistics, M&D Data Science Center, Tokyo Medical and Dental University, Yushima, Bunkyo, Tokyo, Japan