NHS Grampian, University of Oxford - National Perinatal Epidemiology Unit, Queen Mary University of London - Centre for Women's Health, The University of Manchester - Manchester University NHS Foundation Trust, Oxford Fertility - Institute of Reproductive Sciences, University of Aberdeen, University of Southampton, University of Oxford - National Perinatal Epidemiology Unit, University of Birmingham - Tommy’s National Centre for Miscarriage Research, Human Embryology Fertilisation Authority, University of Birmingham, University of London, King's College London, Faculty of Life Sciences & Medicine, King’s College Hospital, University of Nottingham - Nottingham Clinical Trials Unit, King's College London - Assisted Conception Unit, University of Oxford - National Perinatal Epidemiology Unit, Imperial College London, University of Oxford - National Perinatal Epidemiology Unit, University of Copenhagen, The University of Manchester - St Mary’s Hospital, St. Bartholomew’s Hospital (Barts) - Centre for Reproductive Medicine, Nurture Fertility, CARE Fertility, University of Aberdeen - Health Services Research Unit, University of Oxford - National Perinatal Epidemiology Unit (NPEU), Reproductive Science Consultancy, University of Aberdeen and Independent