1. Department of Obstetrics and Gynecology; University of Toyama; Toyama Japan
2. Clinical Laboratory Center; Toyama University Hospital; Toyama Japan
3. Department of Maternal-Fetal Biology; National Research Institute for Child Health and Development; Tokyo Japan
4. Department of Obstetrics and Gynecology; Faculty of Medicine; Fukuoka University; Fukuoka Japan
5. Laboratory of Metagenomics, Graduate School of Frontier Sciences; The University of Tokyo; Kashiwa Japan
6. Graduate School of Advanced Science and Engineering; Waseda University; Tokyo Japan
7. Department of Public Health Faculty of Medicine; University of Toyama; Toyama Japan