1. Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
2. The University of Freiburg’s Faculty of Medicine, Albertstraβe, Freiburg, Germany
3. Faculty of Medicine, Lund University, Sölvegatan, Lund, Sweden
4. Department of Biostatistics, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan