[1] Med Univ Berne, Div Gynaecol Endocrinol & Reprod Med, Bern, Switzerland
[2] Med Univ Heidelberg, Dept Gynaecol Endocrinol & Fertil Disorders, Heidelberg, Germany
[3] Med Univ Bonn, Dept Gynaecol Endocrinol & Reprod Med, Bonn, Germany
[4] Johanna Etienne Hosp Neuss, Dept Obstet & Gynaecol, Neuss, Germany
[5] Amedes Hamburg, Ctr Infertil Prenatal Med Endocrinol & Osteol, Hamburg, Germany
[6] Inselspital Bern, Univ Womens Hosp, Div Gynaecol Endocrinol & Reprod Med, Effingerstr 102, CH-3010 Bern, Switzerland