Temporal trends and regional variations in severe maternal morbidity in Canada, 2003 to 2007

To identify temporal trends and regional variations in severe maternal morbidity in Canada using routine hospitalization data.

We used a previously identified set of International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10CA) and Canadian Classification of Interventions (CCI) codes to estimate rates of severe maternal morbidity in Canada (excluding Quebec) for 2003 to 2007 using the Discharge Abstract Database of the Canadian Institute for Health Information (CIHI). Rates and 95% confidence intervals were calculated by year and within each province and territory and contrasted using the chi-square or Fisher exact test.

The overall rate of severe maternal morbidity was 13.8 per 1000 deliveries (95% CI 13.6 to 14.0). Five provinces or territories had rates that were significantly higher than those in the rest of the country: Newfoundland and Labrador (19.0 per 1000; 95% CI 17.2 to 20.8), Saskatchewan (16.9 per 1000; 95% CI 15.9 to 18.0), Alberta (15.4 per 1000; 95% CI 14.9 to 15.9), Northwest Territories (22.5 per 1000; 95% CI 18.0 to 27.7), and Nunavut (20.2 per 1000; 95% CI 14.2 to 27.8). Rates of some illnesses declined (e.g., eclampsia rates decreased from 12.4 in 2003 to 5.7 per 10 000 deliveries in 2007, P<0.001), while others increased (e.g., postpartum hemorrhage with blood transfusion rates increased from 36.6 in 2003 to 44.3 per 10 000 deliveries in 2007, P<0.001). Interprovincial/territorial contrasts showed several disparities with respect to specific maternal illnesses.

The observed temporal trends and regional disparities in severe maternal morbidity may represent important population health phenomena, and further investigation is required to assess their importance.