Subnational estimates of maternal mortality in Nigeria: Analysis of female siblings’ survivorship histories. 

Abstract BACKGROUND High Maternal Mortality (MM) in Nigeria is further complicated by the lack of reliable estimates for subnational levels such as states and geopolitical regions. Disaggregating maternal mortality estimates by subnational levels is crucial to ensuring policy decisions and program implementation are adapted to areas with a high burden of mortality. This study involves a novel adaptation of small area estimation techniques to derive plausible estimates of levels and trends in Maternal Mortality rates and ratios for states and geopolitical regions in Nigeria. METHODS. Survivorship history data of 293,769 female siblings were provided by 114,154 women in the Nigeria Demographic and Health Surveys of 2008, 2013 and 2018. MM Rates and Ratios were estimated using the Empirical Bayesian technique for small area demographic estimates. The James-Stein estimator was used to shrink the estimates closer to the population mean values with 95% Confidence Interval (CI). RESULTS Levels of MMRatio were highest in the rural areas, States and regions in Northern Nigeria. MMRatio was consistently lower in the South West (2008=281; 2013=367; 2018=392) and higher among the Northern regions of the country, particularly the North-East (2008=654; 2013=612; 2018=901) for three consecutive surveys. Over the three surveys, mortality trends declined about 18% in the North West and 54.2% in the South East region. However, there was a 4.8% increase in MMRatio for South West between 2008 to 2018. CONCLUSIONS Nigeria has geopolitical and sub-national disparities that pose a burden to the country’s maternal health. Since several states in the Northern geopolitical zone still show high maternal mortality, targeted intervention at state levels should be explored to ensure that mothers who need help get it to ensure the sustainable development goals are met.