1. University of Leeds; Centre for Epidemiology and Biostatistics; Bradford Royal Infirmary, Bradford Institute of Health Research Temple Bank House, Duckworth Lane Bradford West Yorkshire UK BD9 6RJ
2. Women and Children's Directorate; Countess of Chester Hospital NHS Trust; Countess of Chester Hospital NHS Trust Liverpool Road Chester South Wirral UK CH2 1UL
3. Queen Elizabeth II Research Institute; NSW Centre for Perinatal Health Services Research; Building DO2 University of Sydney Sydney NSW Australia 2006