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