Sidra Medicine, University of Oxford - National Perinatal Epidemiology Unit, University of Nottingham - Nottingham Clinical Trials Unit, University of Oxford - Nuffield Department of Population Health, University of Oxford - National Perinatal Epidemiology Unit, University of Oxford - National Perinatal Epidemiology Unit, University of Leicester, University of Oxford - National Perinatal Epidemiology Unit, NHS Foundation Trust - Cambridge University Hospitals, University of Oxford - National Perinatal Epidemiology Unit, University of Birmingham, James Cook University Hospital, University of Oxford - National Perinatal Epidemiology Unit (NPEU), James Cook University Hospital, University of Oxford - National Perinatal Epidemiology Unit, University of Leicester - Department of Health Sciences and Independent

University of Nottingham, Government of the United Kingdom - NIHR-Surgical Reconstruction and Microbiology Research Centre, University of Birmingham, Government of the United Kingdom - NIHR-Surgical Reconstruction and Microbiology Research Centre, Government of the United Kingdom - Barts Health NHS Trust, Government of the United Kingdom - Barts Health NHS Trust, Government of the United Kingdom - Birmingham Women's NHS Foundation Trust, University of Birmingham, JYW House - Group B Strep Support, University of Birmingham, University of Birmingham, University of Granada, University of Birmingham - Institute of Metabolism and Systems Research and Independent

University of Birmingham, University of Birmingham, University of Birmingham and University of Birmingham