[1] Miscarriage Assoc, Wakefield, England
[2] Aalborg Univ, Dept Obstet & Gynaecol Aalborg, Aalborg, Denmark
[3] Liverpool Womens Hosp, Dept Gynaecol, Liverpool, Merseyside, England
[4] Univ Hosp Copenhagen, Dept Obstet & Gynaecol, Rigshospitalet, Copenhagen, Denmark
[5] Univ Hosp Copenhagen, Amager & Hvidovre Hosp, Dept Obstet & Gynaecol, Recurrent Pregnancy Unit, Copenhagen, Denmark
[6] Queens Univ Belfast, Ctr Publ Hlth, Sch Med Dent & Biomed Sci, Belfast, Antrim, North Ireland
[7] Radboud Univ Nijmegen, Med Ctr, Dept Internal Med, Nijmegen, Netherlands
[8] ESHRE Cent Off, Strombeek Bever, Belgium
[9] Al Ain Fertil Clin, Al Ain, U Arab Emirates
[10] Univ Warwick, Warwick Med Sch, Div Biomed Sci, Dept Obstet & Gynaecol, Meibergdreef 9, Coventry, W Midlands, England
[11] Univ Copenhagen, Univ Hosp Copenhagen Hvidovre, Dept Clin Med, Copenhagen, Denmark
[12] Leiden Univ, Med Ctr, Dept Obstet & Gynaecol, Leiden, Netherlands
[13] Univ Amsterdam, Med Ctr, Dept Obstet & Gynaecol, Ctr Reprod Med, Amsterdam, Netherlands