1. Department of Obstetrics and Gynecology, Dongguk University Ilsan Hospital, the Graduate School of Medicine of Dongguk University, Goyang, Republic of Korea.
2. Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea.
3. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Severance Hospital, Seoul, Republic of Korea.
4. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.