Objective
We sought to describe a new classification system for contributory factors in, and potential avoidability of, maternal deaths and to determine the contributory factors and potential avoidability among 4 years of maternal deaths in New Zealand.
Study Design
A new classification system for reporting contributory factors in all maternal deaths was developed from previous tools and applied to all maternal deaths in New Zealand from 2006 through 2009.
Results
There were 49 deaths and the maternal mortality ratio was 19.2/100,000 maternities. Contributory factors were identified in 55% of cases. An expert panel identified 35% of maternal deaths as potentially avoidable. In cases where potential avoidability was determined, there were nearly always 2 or 3 domains where contributory factors were identified.
Conclusion
Almost one third of maternal deaths in New Zealand can be considered to be potentially avoidable. This methodology has the potential to identify areas for improvement in the quality of maternity care.
Maternal deaths are devastating events for families. The number of maternal deaths each year in New Zealand varies from 9-15 (Perinatal and Maternal Mortality Review Committee [PMMRC] 2008). In 2005, the New Zealand Minister of Health established the PMMRC for the purpose of reviewing both perinatal and maternal deaths. The strength of mortality review is the ability to review deaths both individually and as aggregated data. From the single examination of cases by experts comes information that might otherwise have been overlooked. From the aggregated data come broader themes and trends that can be identified and monitored and with appropriate policy changes and interventions might lead to improvements in outcomes.
See related editorial, page 293
Mortality review should not only focus on definitions and causation of disease but also needs to focus on modifiable features in health systems and the quality of clinical care. With this in mind, the PMMRC sought to report not only clinical data but also contributory factors and potential avoidability. For example, a woman with preeclampsia dies at 38 weeks from a cerebral hemorrhage and on review of the case the management of hypertension was found to be outside standard practice. This death would be classified as a direct maternal death from hypertension with contributory factors that might include inadequate protocols or guidelines, failure to follow standard practice, and failure to appreciate the seriousness of the condition. The death can therefore be considered potentially avoidable.
It has been suggested that even in the developed world 50% of all maternal deaths are potentially avoidable. A number of models of reporting contributory factors have already been developed. None of these systems adequately met our requirements for identifying potential avoidability. Some failed to provide adequate documentation of the process. For example, we were unable to find a definition of substandard care or the methodology used by Centre for Maternal and Child Enquiries (CMACE). Other models covered some dimensions well but were not comprehensive. For example, we sought to report on barriers to accessing or engaging with care and yet none of the classification systems encompassed this dimension. In the case of root cause analysis, it was thought that this only addressed system issues and did not consider the contribution of clinical competence. The aim of this report is to, first, describe a new classification system for contributory factors incorporating the best of these approaches and, second, to determine the contributory factors and potential avoidability among 4 years of maternal deaths in New Zealand.
Materials and Methods
The Maternal Mortality Review Working Group (MMRWG) of the PMMRC is responsible for reviewing all maternal deaths in New Zealand. The members of the working group include obstetricians, midwives, an anesthetist, a psychiatrist, a health care manager, and a pathologist.
Definitions
In New Zealand, a maternal death is defined as the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the duration and site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management, but not from accidental or incidental causes.
The maternal mortality ratio is calculated per 100,000 maternities and follows this CMACE approach. Maternities are defined as all live births and fetal deaths at ≥20 weeks or weighing ≥400 g if gestation unknown. Pregnancies ending <20 weeks are not included in this working definition because the absolute number of pregnancies ending before this time is unknown.
The definitions adopted by the MMRWG are based on the World Health Organization definitions from the International Statistical Classification of Diseases, 10th Revision and the cause of each death is subclassified, using the CMACE system :
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Direct maternal deaths : those resulting from obstetric complications of the pregnant state (pregnancy, labor, or puerperium); from interventions, omissions, incorrect treatment; or from a chain of events resulting from the above.
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Indirect maternal deaths : those resulting from previous existing disease or disease that developed during pregnancy and not due to direct obstetric causes, but aggravated by the physiologic effects of pregnancy.
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Coincidental maternal deaths : those resulting from unrelated causes that happen to occur in pregnancy or the puerperium.
Development of a new classification system for contributory factors
The classification system was developed iteratively following a literature search for similar models, in discussion with the PMMRC, the MMRWG, local coordinators, and Ministry of Health officials of the Quality Improvement Committee. The published classification systems considered in the development of this system for New Zealand include the following:
- 1
CMACE identifies cases of substandard care and considers the following contributory factors: failures in diagnosis and treatment, errors in management of complications, failures in the organization of health care (structure), and patient factors such as late presentation for treatment, barriers to access to care, social situation, family violence, and drug use. The definition for substandard care (major) is “Contributed significantly to the death of the mother. In many, but not all cases, different treatment may have altered the outcome.” No description of the methods used to identify the contributory factors or substandard care is provided within the report or referenced.
- 2
The London protocol for reviewing critical incidents contains a framework of contributory factors that includes the following: institutional (medicolegal and regulatory), organization and management (financial and policies), work environment (staffing levels and skills mix, the equipment and administrative and management support), team (communication, supervision, leadership), individual staff member (knowledge and skills), tasks (protocols, accuracy and availability of diagnostic tests), and the patient (the complexity of their condition, language, and social factors). This tool was a useful starting point for the methodology developed.
- 3
The Geller model for scoring preventability includes provider- and system-related preventability. Morbidity and mortality cases were assessed by a multidisciplinary team of experts to reach a consensus on classification of death as preventable or not. Preventability was described as “action or inaction on the part of the health care provider, system or patient that may have caused or contributed” to the adverse outcome. A descriptive model for identifying provider- and system-related preventability notes 10 categories to assess but they have not included patient factors in this model. Geller et al, however, does comment on noncompliance as a contributory factor, stating patient factors as being social factors that limit their ability to access health care as well as actions or delays by the patient that contributed to the death.
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Root cause analysis approach for identifying factors includes policies, communication, training and competency, fatigue, scheduling, environment, and equipment factors. Patient factors are not included as causal factors nor is the family included in the mortality review process, citing confidentiality.
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In the preventability scale of the Perinatal and Infant Mortality Committee of Western Australia, the preventability of an adverse event is defined as “an error in management due to failure to follow accepted practice at the individual or system level” and accepted practice is taken to be “the current level of expected performance for the average practitioner or system that manages the patient” and are based on the preventability score used in the Quality in Australian Health Care Study. This system does not appear to address barriers to accessing and engaging with care.
The new system for classifying potentially avoidable deaths
Following the presentation of each maternal death the role of contributory factors is considered. There are 2 steps. In the first step, the following questions that identify contributory factors are considered:
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Have any organizational and/or management factors been identified?
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Have factors relating to personnel been identified?
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Have factors relating to technology and equipment been identified?
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Have factors relating to environment been identified?
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Have barriers to accessing/engaging with care been identified?
Examples of these and the subcategories within each are given in the PMMRC Contributory Factors Form ( Table 1 ).
| Have any organizational and/or management factors been identified? |
| Poor organizational arrangements of staff |
| Inadequate education and training |
| Lack of policies, protocols, or guidelines |
| Inadequate numbers of staff |
| Poor access to senior clinical staff |
| Failure or delay in emergency response |
| Delay in procedure, eg, cesarean section |
| Inadequate systems/process for sharing of clinical information between services |
| Delayed access to test results or inaccurate results |
| Other reason |
| Have factors relating to personnel been identified? |
| Knowledge and skills of staff were lacking (includes failure to maintain competence) |
| Delayed emergency response by staff |
| Failure of communication between staff |
| Failure to seek help/supervision |
| Failure to offer or follow recommended best practice |
| Lack of recognition of complexity or seriousness of condition |
| Other reason |
| Have factors relating to technology and equipment been identified? |
| Essential equipment not available |
| Lack of maintenance of equipment |
| Malfunction/failure of equipment |
| Failure/lack of information technology |
| Other reason |
| Have factors relating to environment been identified? |
| Geography, eg, long-distance transfer |
| Building and design functionality limited clinical response |
| Other reason |
| Have barriers to accessing/engaging with care (eg, no, infrequent, or late booking for antenatal care; woman declined treatment/advice) been identified? |
| Substance use |
| Lack of recognition of complexity or seriousness of condition (by either woman or her family) |
| Maternal mental illness |
| Cultural barriers |
| Language barriers |
| Not eligible to access free care |
| Family violence |
| Other reason |
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