[1] Yonsei Univ, Severance Hosp, Dept Obstet & Gynecol, Coll Med, Seoul, South Korea
[2] Yonsei Univ, Coll Med, Inst Womens Life Med Sci, Dept Obstet & Gynecol, Seoul, South Korea
[3] Yonsei Univ, Coll Med, Yongin Severance Hosp, Dept Obstet & Gynecol, Yongin, South Korea
[4] Yonsei Univ, Coll Med, Gangnam Severance Hosp, Seoul, South Korea
[5] Yonsei Univ, Severance Hosp, Dept Obstet & Gynecol, Coll Med, 50-1 Yonsei Ro, Seoul 03722, South Korea