1. WHO 2016 Maternal Mortality fact sheet www.who.int/mediacentre/factsheets/fs348/en/
2. UNICEF 2017 UNICEF Data: Monitoring the Situation for Women and Children, Statistics by Topic, Maternal Health, Maternal Mortality https://data.unicef.org/topic/maternal-health/maternal-mortality/
3. WHO analysis of causes of maternal death: a systematic review;Khan;Lancet,2006
4. United Nations 2015 Sustainable Development Goals http://www.un.org/sustainabledevelopment/health/