[1] Seoul Natl Univ, Coll Med, Dept Obstet & Gynecol, Seoul 110744, South Korea
[2] Maastricht Univ, Nutr & Toxicol Res Inst Maastricht, Dept Epidemiol, Maastricht, Netherlands
[3] Karolinska Inst, Natl Inst Environm Med, Stockholm, Sweden
[4] Seoul Natl Univ, Bundang Hosp, Dept Obstet & Gynecol, Songnam, South Korea
[5] Ewha Womans Univ, Coll Med, Dept Obstet & Gynecol, Seoul, South Korea
[6] Seoul Natl Univ, World Class Univ, Seoul 110744, South Korea