Centre for Reproductive Medicine, St. Bartholomew's Hospital, London, UK. Fertility and Assisted Reproduction, Homerton University Hospital, Queen Mary University of London, London, UK. Monash Centre for Health Research and Implementation, Monash University, Clayton, Vic., Australia. Tommy's National Centre for Miscarriage Research, University of Birmingham, Birmingham, UK. Women's Health Research Unit, The Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.