1. Institute of Applied Health Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
2. Department of Obstetrics and Gynaecology, Nottingham Clinical Trials Unit, University of Nottingham, Nottingham, UK
3. Department of Obstetrics and Gynaecology, Guy’s and St Thomas’ Hospital, Guy’s and St Thomas’ NHS Foundation Trust, London, UK
4. Department of Obstetrics and Gynaecology, Birmingham Women’s and Children’s NHS Foundation Trust, UK
5. Department of Obstetrics and Gynaecology, University of Leeds, Leeds, UK
6. University of Bristol, Bristol, UK
7. Department of Obstetrics and Gynaecology, Imperial College London, London, UK