1. Department of Obstetrics and Gynecology, University of Indonesia, Cipto Mangunkusumo National Hospital, Jakarta, Indonesia, Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan
2. Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan,
3. Department of Obstetrics and Gynecology, Showa University School of Medicine, Tokyo, Japan
4. Department of Histology and Embryology Division of Prenatal Medicine, University of Bologna, Bologna, Italy