Acknowledging uncertainty about maternal mortality estimates

Differences between estimates of maternal mortality from different research groups have been much debated. The data that are included or omitted and the choice of models have been discussed, but the uncertainty of the estimates has not received much attention. Attempts to estimate the maternal mortality ratio (MMR) for South Africa published in the past five years illustrate the large variability of estimates and the tendency to underestimate uncertainty, particularly when MMR is low. Unless a country has a nationally representative system to track maternal deaths, there is likely to be a great deal of uncertainty about maternal mortality. Currently this uncertainty is not being fully acknowledged by those attempting to estimate MMR indirectly, particularly as part of efforts to track maternal mortality globally. This, together with the fact that estimates of MMR can change significantly from one set of estimates to the next, make them useless for informing countries about what is or is not working to combat maternal mortality.