1. Cameron MJ, Robson SC (2006) Vital statistics: an overview. In: Lynch CB, Keith L, Lalonde AB and Karoshi M (eds) A textbook of postpartum hemorrhage. Sapiens Publishing, Duncow, Kirkmahoe, Dumfrieshire, UK, Chap 3, pp 17–34
2. Ronsmans C, Graham WJ (2006) Maternal mortality: who, when, and why. Lancet 368(9542):1189–1200. doi: 10.1016/S0140-6736(06)69380-X
3. Lewis G (ed) (2004) The confidential enquiry into maternal and child health (CEMACH). Why mothers’ die—2000–2002. The sixth report on confidential enquiries into maternal deaths in the United Kingdom. RCOG Press, London
4. Lewis G (ed) (2007) The confidential enquiry into maternal and child health (CEMACH). Saving mothers’ lives: reviewing maternal deaths to make motherhood safer: 2003–2005. The seventh report on confidential enquiries into maternal deaths in the United Kingdom. RCOG Press, London
5. Razvi K, Chua S, Arulkumaran S, Ratnam SS (1996) A comparison between visual estimation and laboratory determination of blood loss during the third stage of labour. Aust NZ J Obstet Gynaecol 36(2):152–154