[1] Kings Coll London, Guys & St Thomas NHS Trust, Assisted Concept Unit, London WC2R 2LS, England
[2] Univ Birmingham, Birmingham Womens Hosp, Acad Unit, Birmingham, W Midlands, England
[3] Lister Hosp London, Lister Fertil Clin, London, England
[4] Kings Coll London, Assisted Concept Unit, London WC2R 2LS, England
[5] Guys & St Thomas NHS Trust, Assisted Concept Unit, London, England