[1] Johannes Gutenberg Univ Mainz, Dept Obstet & Gynecol, Univ Med Ctr, Mainz, Germany
[2] Fetal Med Res Inst, Kings Fertil, London, England
[3] Univ Freiburg, Med Ctr, Dept Obstet & Gynecol, Freiburg, Germany
[4] Freelance Statistician Analyzing Consulting Traini, Chemnitz, Germany
[5] Tech Univ Munich, Sch Med & Hlth, Dept Obstet & Gynecol, Klinikum Rechts Isar, Munich, Germany
[6] Univ Clin Inselspital Bern, Dept Obstet & Gynecol, Bern, Switzerland
[7] Goethe Univ Frankfurt, Univ Med, Dept Obstet & Gynecol, Div Gynecol Endocrinol & Reprod Med, Frankfurt, Germany