[1] Univ Amsterdam, Acad Med Ctr, Ctr Reprod Med, NL-1105 AZ Amsterdam, Netherlands
[2] Vrije Univ Amsterdam, Med Ctr, Dept Obstet & Gynaecol, Amsterdam, Netherlands
[3] Natl Womens Hlth, Fertil PLUS, Auckland, New Zealand
[4] Univ Aberdeen, Sch Med, Aberdeen AB9 1FX, Scotland
[5] Univ Med Ctr, Dept Obstet & Gynaecol, Utrecht, Netherlands