Severe maternal morbidity in Canada, 1991-2001

Abstract

Background: Although death rates are often used to monitor the quality of health care, in industrialized countries maternal deaths have become rare. Severe maternal morbidity has therefore been proposed as a supplementary indicator for surveillance of the quality of maternity care. Our purpose in this study was to describe severe maternal morbidity in Canada over a 10-year period, among women with or without major pre-existing conditions. Methods: We carried out a retrospective cohort study of severe maternal morbidity involving 2 548 824 women who gave birth in Canadian hospitals between 1991 and 2000. Thirteen conditions that may threaten the life of the mother (e.g., eclampsia) and 11 major pre-existing chronic conditions (e.g., diabetes) that could be identified from diagnostic codes were noted. Results: The overall rate of severe maternal morbidity was 4.38 per 1000 deliveries. The fatality rate among these women was 158 times that of the entire sample. Rates of venous thromboembolism, uterine rupture, adult respiratory distress syndrome, pulmonary edema, myocardial infarction, severe postpartum hemorrhage requiring hysterectomy, and assisted ventilation increased substantially from 1991 to 2000. The presence of major pre-existing conditions increased the risk of severe maternal morbidity to 6-fold. Interpretation: Severe maternal morbidity occurs in about 1 of 250 deliveries in Canada, with marked recent increases in certain morbid conditions such as pulmonary edema, myocardial infarction, hemorrhage requiring hysterectomy, and the use of assisted ventilation.Cite this article as CMAJ 2005;173(7).

Beyond maternal death: improving the quality of maternal care through national studies of ‘near-miss’ maternal morbidity

“…Our findings suggest that the association of older maternal age and obesity with increased odds of dying observed in the CMACE/UKOSS study 160 could be mediated to some extent through medical comorbidities. Unlike other studies, 25,153 we did not find pre-existing diabetes mellitus and cardiac conditions to be associated with maternal death. Whether or not this reflects improved obstetric care of women with diabetes and cardiac disease is unclear and requires further research.…”

“…Studies in other developed countries have investigated near-miss maternal morbidity through routine sources of data, [22][23][24][25] but these studies are limited in their scope to identify risk factors by incomplete information on potential confounders. 26 In addition, the use of routine data means that these studies are unable to investigate diagnosis and management and hence provide evidence to improve clinical care.…”

“…Several studies have demonstrated individual medical comorbidities, such as pre-existing asthma, hypertension, malignancy, chronic ischaemic and congenital heart disease, chronic renal disease, systemic lupus erythematosus, hypercoagulability states, human immunodeficiency virus and diabetes mellitus, to be associated with both severe maternal morbidity and mortality, 25,153,[162][163][164][165][166][167][168] but the extent of the population risk attributable to medical comorbidities as a whole in the UK has not previously been quantified. Uptake of antenatal care was found to be poorer among women with medical comorbidities in our study population, which could increase the adverse effects associated with these conditions.…”

Predictors of maternal mortality and near-miss maternal morbidity

“…Studies have investigated severe acute maternal morbidity or 'near-miss' as a surrogate for evaluating obstetric care. [4][5][6][7] There is great variation in published studies in defining near-miss. 8,9 A 1-year prospective multi-center study defined 'near-miss' as an acute organ system dysfunction, which if not treated appropriately, could result in death.…”

“…13 Another large retrospective study estimated the incidence and predictors of severe obstetric morbidity, which was defined as severe pre-eclampsia, eclampsia, hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome, severe hemorrhage, severe sepsis and uterine rupture. 7 Geller et al 14,15 have proposed a scoring system to classify women with severe morbidity and nearmiss morbidity. These studies have suggested that the identification of risk factors for severe morbidity may improve maternal care.…”