1. World Health Organization. Maternal Mortality. Available from: http://www.who.int/mediacentre/ factsheets/fs348/en/
2. Prawirohardjo S, editors. Ilmu Kebidanan. 4th ed. Jakarta: PT Bina Pustaka Sarwono Prawirohardjo; 2014.
3. Siveska J, Jasovic V, Stoilova, S. Previous Preg-nancy history, parity, maternal age and risk of pregnancy induced hypertension. British Medical Journal. 2011;112(4):188-91.
4. El-moselhy E, Khalifa H, Amer S, et al. Risk Factor and impacts of pre-eclamp-sia: an epidemiological study among pregnant mothers in Cairo, Egypt. Journal of American Science. 2011;7(5):311-23.
5. Etika DS, Hariyamto, Elfrida S. Hubungan antara usia dengan preeklampsia pada ibu hamil di POLI KIA RSUD Kefamenanu Kabupaten Timor Tengah Utara. Jurnal Delima Harapan. 2014;3(2):10-19