Validating the WHO Maternal Near Miss Tool in a high-income country

This study was performed to assess the applicability of the WHO Maternal Near Miss Tool (MNM Tool) and the organ dysfunction criteria in a high-income country.

The MNM tool was applied to 2552 women who died of pregnancy-related causes or sustained severe acute maternal morbidity between August 2004 and August 2006 in one of the 98 hospitals with a maternity unit in the Netherlands. Fourteen (0.6%) cases had insufficient data for application. Each case was assessed according to the three main "MNM categories" specified in the MNM tool and their subcategory criteria: five disease-, four intervention- and seven organ dysfunction-based criteria. Potentially life-threatening conditions (disease-based inclusions) and life-threatening cases (organ dysfunction-based inclusions) were differentiated according to WHO methodology. Outcomes were incidence of all (sub)categories and case-fatality rates.

Of the 2538 cases, 2308 (90.9%) women fulfilled disease-based, 2116 (83.4%) intervention-based and 1024 (40.3%) organ dysfunction-based criteria. Maternal death occurred in 48 women, of whom 23 (47.9%) fulfilled disease-based, 33 (68.8%) intervention-based and 31 (64.6%) organ dysfunction-based criteria. Case-fatality rates were 23/2308 (1.0%) for cases fulfilling the disease-based criteria, 33/2116 (1.6%) for intervention-based criteria and 31/1024 (3.0%) for women fulfilling the organ dysfunction-based criteria.

In the Netherlands, where advanced laboratory and clinical monitoring are available, organ dysfunction-based criteria of the MNM tool failed to identify nearly two-thirds of sustained severe acute maternal morbidity cases and more than one-third of maternal deaths. Disease-based criteria remain important, and using only organ dysfunction-based criteria would lead to underestimating severe acute maternal morbidity.