[1] Univ Groningen, Univ Med Ctr Groningen, Dept Obstet & Gynecol, NL-9700 RB Groningen, Netherlands
[2] Univ Groningen, Univ Med Ctr Groningen, Dept Endocrinol, NL-9700 RB Groningen, Netherlands
[3] Twenteborg Hosp, Dept Internal Med Endocrinol, NL-7600 SZ Almelo, Netherlands