The prevalence of maternal near miss: a systematic review

Severe maternal morbidity or 'near miss' is a promising indicator to improve quality of obstetric care.

To systematically review all available studies on 'near miss'.

Following a pre-defined protocol, our review covered articles between January 2004 and December 2010. We used a combination of the following terms: near miss morbidity, severe maternal morbidity, severe acute maternal morbidity, obstetric near-miss, maternal near miss, obstetric near miss, emergency hysterectomy, emergency obstetric hysterectomy, maternal complications, pregnancy complications, intensive care unit.

Nearly 4000 articles were screened by title and abstract, and 153 articles were retrieved for full text evaluation. There were no language restrictions.

Data extraction was performed using an instrument that included sections on study characteristics, quality of reporting, prevalence/incidence and the definition and identification criteria. Univariate analysis and meta-analysis for sub-groups were performed.

A total of 82 studies from 46 countries were included. Criteria for identification of cases varied widely. Prevalence rates varied between 0.6 and 14.98% for disease-specific criteria, between 0.04 and 4.54% for management-based criteria and between 0.14 and 0.92% for organ-based dysfunction based on Mantel criteria. The rates are higher in low-income and middle-income countries of Asia and Africa. Based on meta-analysis, the estimate of near miss was 0.42% (95% CI 0.40-0.44%) for the Mantel (organ dysfunction) criteria and 0.039% (95% CI 0.037-0.042%) for emergency hysterectomy. Our meta-regression results indicate that emergency hysterectomy rates have been increasing by about 8% per year.

There is growing interest in the application of the maternal near-miss concept as an adjunct to maternal mortality. However, in the literature published before 2011 there was still important variation in the criteria used to identify maternal near-miss cases. The World Health Organization recently published criteria based on markers of management and of clinical and organ dysfunction which would enable systematic data collection on near miss and development of summary estimates. Comparing the rates over time and across regions, it is clear that different approaches are needed to lower the rates of near miss and that interventions must be developed with the local context in mind.