[1] Univ Nijmegen, Ctr Med, Dept Obstet & Gynecol, Nijmegen, Netherlands
[2] Univ Nijmegen, Ctr Med, Dept Chem Endocrinol, Nijmegen, Netherlands
[3] Univ Nijmegen, Ctr Med, Dept Gastroenterol, Nijmegen, Netherlands
[4] Erasmus Univ, Med Ctr, Dept Obstet & Gynecol, Rotterdam, Netherlands