RT Journal Article SR Electronic T1 Severe maternal morbidity in Canada, 1991–2001 JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP 759 OP 764 DO 10.1503/cmaj.045156 VO 173 IS 7 A1 Shi Wu Wen A1 Ling Huang A1 Robert Liston A1 Maureen Heaman A1 Tom Baskett A1 I.D. Rusen A1 K.S. Joseph A1 Michael S. Kramer A1 for the Maternal Health Study Group, Canadian Perinatal Surveillance System YR 2005 UL http://www.cmaj.ca/content/173/7/759.abstract AB 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.