ArticlesNational, regional, and worldwide estimates of stillbirth rates in 2009 with trends since 1995: a systematic analysis
Introduction
In 2006, two sets of stillbirth rate estimates for 2000 were published—one by WHO1 and one by the Saving Newborn Lives/Initiative for Maternal Mortality Programme Assessment (IMMPACT).2 These reports were the first published national estimates of stillbirth rates. Both generated similar worldwide totals—3·3 million1 and 3·2 million2 stillbirths in 2000—and, in some cases, similar regional totals. These worldwide estimates are similar to the worldwide total of early neonatal deaths in 2000 (3·0 million) and are higher than the yearly total of deaths from HIV/AIDS in 2004 (1·8 million).3 Despite the similarities between the two reports, the estimated country-specific rates differed substantially for several countries, with differences of a factor of two to three for some countries (figure 1).
We use the WHO-agreed definition of stillbirth for international comparison (≥1000 g birthweight or ≥28 completed weeks of gestation).1, 4, 5 We identified several areas that need attention to develop the previous work and to take into account recent advances and debates on worldwide estimates.6 We sought to broaden and update the input data, particularly from low-income countries, and to use the neonatal mortality rate rather than the infant mortality rate as a model predictor, because the neonatal mortality rate is more closely associated with factors affecting stillbirth (eg, care during pregnancy and around the time of birth). Both the WHO1 and Saving Newborn Lives/IMMPACT2 stillbirth estimates had difficulties with generation of plausible estimates for high-mortality countries, partly because of the scarce availability of data of reasonable quality from sub-Saharan Africa and Asia. In response to this difficulty, both groups made post-modelling adjustments to their estimates for several countries. We estimate that these adjustments resulted in increases in the estimated number of worldwide stillbirths of 565 000 (WHO)1 and 670 000 (Saving Newborn Lives/IMMPACT),2 which is equivalent to increases of 17% and 21%, respectively, in the worldwide number of stillbirths. In this new exercise undertaken jointly with WHO, we aimed to avoid such adjustments to the estimates.
In this Article, we estimate national, regional, and worldwide stillbirth rates and numbers for 193 countries in 2009, retrospectively estimating to 1995 using the same model, and we provide a quantitative assessment of the uncertainty of these estimates. We also present detailed individual-country rates for 2008 for ease of comparison with existing data on neonatal and maternal mortality rates.
Section snippets
Data inputs
The input dataset was compiled from three sources. First, data from countries with vital registration systems that report stillbirths, or with specific perinatal mortality reporting systems, were identified; if the data were available, these were accessed and assessed for inclusion. We accessed data from national stillbirth registries, including Euro-Peristat and national statistical websites.7, 8, 9, 10, 11, 12 Additionally, the International Stillbirth Alliance requested data based on the
Results
The final dataset used (figure 2) comprised 1149 datapoints for stillbirth rate, after exclusion of 39 datapoints as implausible outliers (37 with a stillbirth rate to neonatal mortality rate ratio of <0·25, and two with a stillbirth rate to neonatal mortality rate ratio of >4·0). 527 datapoints (45·9%), with a median reference year of 2002 were from countries in regions of low neonatal mortality; 467 datapoints (40·6%; 2002) were from countries in regions of moderate neonatal mortality; and
Discussion
We estimated yearly national stillbirth rates and numbers from 1995 to 2009. The estimated number of global stillbirths was 2·64 million in 2009 compared with 3·03 million in 1995. In view of the expanded and updated input data, especially with a systematic country consultation and improved modelling, including avoidance of post-modelling adjustments in countries with high stillbirth mortality rates, these results provide more accurate and updated data than do the two previous studies to
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