1. National Perinatal Epidemiology Unit (NPEU); Nuffield Department of Population Health; University of Oxford; Oxford UK
2. The Royal Wolverhampton Hospital NHS Trust; New Cross Hospital; Wolverhampton UK
3. Guy's and St Thomas’ NHS Foundation Trust; Guy's Hospital; London UK
4. St Thomas’ Hospital; London UK
5. Transfusion Medicine, NHS Blood and Transplant; John Radcliffe Hospital; Oxford UK
6. Department of Haematology; Oxford University Hospitals NHS Foundation Trust; Oxford UK
7. Radcliffe Department of Medicine; University of Oxford and Oxford BRC Haematology Theme; Oxford UK