Division of Population and Lifespan Sciences, Department of Obstetrics and Gynaecology (N.W.J., J.G.T., K.F.W.), and Nottingham Clinical Trials Unit (E.J.M., N.W.), University of Nottingham, Nottingham; National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford (M.K.); and Neonatal Intensive Care Unit, University Hospital Southampton NHS Foundation Trust, Southampton (J.D.), United Kingdom