Report on Maternal Mortality in Canada

on the occasion of World Health Day, April 7, 1998, devoted to the theme of Safe Motherhood

During the 20th century risks to women associated with childbirth in developed countries have been dramatically reduced as a result of many factors. These include technological advancements in obstetrical care, greater access to health services and fewer births occurring at the extremes of women's reproductive age span. The reported maternal mortality ratio in Canada has declined from approximately 500 maternal deaths per 100,000 live births in the early 1920s to less than 5 per 100,000 live births in the 1990s¹, among the lowest reported maternal mortality ratios in the world.²

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Why is this issue important in Canada where childbirth is known to be relatively safe?

Canadian women are fortunate to have universal access to health care contributing to the safety of pregnancy and childbirth. It is nevertheless important to monitor patterns of pregnancy-related mortality and serious morbidity (illness) and to be sensitive to what observed patterns or changes may tell us in order to continue to safeguard women during this critical period. Because many developed countries have found maternal deaths to be seriously underreported³, the monitoring process must begin with ascertainment of the accuracy of routine reporting of deaths associated with pregnancy and childbirth in Canada. The addition of the categories "late maternal deaths" and "pregnancy-related deaths" (defined below) to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10), recognizes that deaths from any cause related to or aggravated by pregnancy may not be counted as maternal deaths because they occurred more than 42 days after the termination of the pregnancy, or because they may have been misclassified under other ICD-9 categories.

The Canadian Study of Maternal Mortality and Morbidity is being conducted under the auspices of Health Canada's Canadian Perinatal Surveillance System

The Canadian Perinatal Surveillance System (CPSS), a program of Health Surveillance and Epidemiology Division, is part of Health Canada's Public Health Intelligence initiative. The CPSS subcommittee studying maternal mortality comprizes health professionals, epidemiologists and representatives from Statistics Canada and the Society of Obstetricians and Gynaecologists of Canada (SOGC).

What are the objectives of the Canadian Study of Maternal Mortality and Morbidity?

• To determine the extent of underreporting of maternal mortality in Canada during five target years (1988-1992) by examining the cause of death recorded for all women who died within a year of a live birth or still birth. (Deaths are identified through a record linkage process using vital records housed at Statistics Canada that originate from the provinces and territories.)

• To determine cause-specific death rates within a year of a pregnancy outcome for women whose death was not classified as a maternal death, and to compare these rates with cause-specific death rates among women not known to have been pregnant within the preceding year. This will include comparisons of rates of suicide, homicide and other traumatic causes.

• To explore approaches to defining and quantifying serious pregnancy-related morbidity in Canada nationally.

• To document trends and/or regional differences in defined indicators of serious pregnancy-related morbidity.

Definitions of maternal mortality

ICD-9 definition:⁴ Maternal death is "death while pregnant or within 42 days of the termination of pregnancy, irrespective of the duration and the site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management but not from accidental or incidental causes."

ICD-10 definition:⁵ Maternal death as defined in ICD-9, with the addition of the following:

Late Maternal Deaths: deaths from direct or indirect obstetric causes more than 42 days but less than one year after the termination of pregnancy.

Pregnancy-related Deaths: deaths while pregnant or within 42 days of the termination of pregnancy, irrespective of the cause.

References

1. Statistics Canada. Selected mortality statistics, Canada, 1921-1990. Ottawa, Ont.: Statistics Canada, 1994. (Catalogue 82-548.)
2. Unicef. The state of the world's children 1997. Toronto, Ont.: Oxford University Press, 1997.
3. Atrash HK, Alexander S, Berg C. Maternal mortality in developed countries: not just a concern of the past. Obstet Gynecol 1995;86:700-705.
4. World Health Organization. International classification of diseases, 1975 revision. Geneva: WHO 1977;1:764.
5. World Health Organization. International statistical classification of diseases and related health problems, 10th revision. Geneva: WHO 1992;1:1238.

Contact for further information: Linda Turner, PhD, Consultant Epidemiologist
Health Surveillance and Epidemiology Division
Public Health Agency of Canada
Health Canada
PL 0601E2, Tunney's Pasture
Ottawa, Ontario K1A 0L2
E-mail: cpss@hc-sc.gc.ca
Internet: www.phac-aspc.gc.ca/rhs-ssg/