1 Birmingham Clinical Trials Unit, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK. Electronic address: [email protected].
2 Department of Health Sciences, University of Leicester, Leicester, UK.
3 National Perinatal Epidemiology Unit Clinical Trials Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
4 Institute of Applied Health Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK.
5 CLAHRC South London, Kings College London, London, UK.
6 National Childbirth Trust, London, UK.
7 Centre for Health Economy, Australian Hearing Hub, Macquire University, Sydney, NSW, Australia.