Severe maternal morbidity in Canada, 1991-2001

Area of Science:

• Obstetrics and Gynecology
• Public Health Surveillance
• Maternal Health Outcomes

Background:

• Maternal deaths are rare in industrialized nations, necessitating alternative quality indicators.
• Severe maternal morbidity is proposed as a key indicator for monitoring maternity care quality.
• Understanding severe maternal morbidity trends is crucial for improving maternal health surveillance.

Purpose of the Study:

• To describe the incidence and trends of severe maternal morbidity in Canada.
• To analyze severe maternal morbidity in women with and without major pre-existing conditions.
• To identify specific severe maternal conditions with increasing prevalence.

Main Methods:

• Retrospective cohort study of 2,548,824 deliveries in Canadian hospitals (1991-2000).
• Inclusion of 13 life-threatening maternal conditions and 11 major pre-existing chronic conditions identified via diagnostic codes.
• Analysis of severe maternal morbidity rates and associated risk factors.

Main Results:

• Overall severe maternal morbidity rate was 4.38 per 1000 deliveries.
• Fatality rate among women with severe morbidity was 158 times higher than the general sample.
• Significant increases observed in venous thromboembolism, uterine rupture, ARDS, pulmonary edema, myocardial infarction, hysterectomy for hemorrhage, and assisted ventilation.
• Major pre-existing conditions increased the risk of severe maternal morbidity sixfold.

Conclusions:

• Severe maternal morbidity occurs in approximately 1 in 250 deliveries in Canada.
• Certain severe conditions, including pulmonary edema, myocardial infarction, hemorrhage requiring hysterectomy, and assisted ventilation, show marked recent increases.
• Pre-existing maternal conditions are a significant risk factor for severe maternal morbidity.