1. Department of Health Policy, National Research Institute for Child Health and Development, Tokyo, Japan.
2. Inomata Children's Clinic, Chiba, Japan.
3. Department of Research & Development, Aiiku Maternal and Child Health Center, Tokyo, Japan.
4. Department of Obstetrics, Gynecology and Molecular Reproduction Science, Graduate School of Medicine, Yokohama City University, Yokohama, Japan.
5. Japan Association of Obstetrics and Gynecologists (JAOG) Birth Defects Monitoring Program, Yokohama, Japan.