1. Center for Regenerative Medicine, National Center for Child Health and Development, and Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan
2. Department of Social Medicine, National Center for Child Health and Development, and Department of Obstetrics and Gynecology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
3. Department of Social Medicine, National Center for Child Health and Development, Tokyo, Japan
4. Department of Obstetrics and Gynecology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
5. Department of Reproductive Medicine, Chiba University Graduate School of Medicine, and Department of Obstetrics and Gynecology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan