Introduction: The maternal mortality ratio (MMR) is a key indicator for measurement of progress against Millennium Development Goal 5 (MDG 5). For many countries, especially those with a presumed high number of maternal deaths, only estimates are available.
Sources of data: Recent global estimates and the reasons for high maternal mortality are reviewed.
Areas of agreement: There is international consensus that efforts to reduce maternal mortality globally need to be intensified.
Areas of controversy: Many countries lack accurate data on number of deaths in women of reproductive age and number of births. Therefore, statistical modelling has been used to calculate estimates, which generally have wide confidence intervals and may be disputed by individual countries.
Growing points: There is renewed focus on MMR as 2015 approaches.
Areas timely for developing research: There is a need to adapt and implement methods for measuring maternal mortality to generate more accurate estimates. More data on cause of death are needed.