Spatial Analysis of Pregnancy Complications Associated with Maternal Cardiovascular Disease Risk in Ontario

Queen’s University, Master’s thesis, 31 July 2012

Jessica Stortz

“Aim: The aim of this study was to: 1) investigate the geographic distribution of six pregnancy complications associated with future maternal cardiovascular disease risk in the province of Ontario and 2) to identify regions where women are likely to benefit from post-partum cardiovascular disease screening, based on the development of complications during pregnancy.

“Rationale: Cardiovascular disease is the leading cause of death in Canadian women. Pregnancy has been likened to a cardiovascular stress test and provides an early opportunity to assess a female’s lifetime risk of cardiovascular disease.

Age-standardized cumulative incidence of gestational diabetes by Public Health Unit area in Ontario (2005-2009)

Age-standardized cumulative incidence of gestational diabetes by Public Health Unit area in Ontario (2005-2009)

“Methods: This study was a retrospective analysis of data collected for the Niday Perinatal Database, provided by the Better Outcomes Registry & Network. Crude and age-standardized cumulative incidences of six pregnancy complications, and one or more pregnancy complications, were calculated for each Public Health Unit area in Ontario. The cumulative incidence of one or more pregnancy complications for women with no previous history of cardiovascular disease or traditional cardiovascular risk factors was calculated at the Public Health Unit and census subdivision area levels. Spatial statistics were applied to locate statistically significant clusters of high cumulative incidence.

“Results: Crude and age-standardized cumulative incidences of each pregnancy complication and one or more pregnancy complications varied across Public Health Unit areas in Ontario. The crude cumulative incidence of one or more complications ranged from 74 to 224 cases per 1000 pregnancies. The spatial analysis identified one statistically significant cluster of high cumulative incidence at the Public Health Unit area level, spanning the Lambton, Chatham-Kent, and Windsor-Essex Health Unit areas. Seven statistically significant clusters of high cumulative incidence census subdivisions were located within the following Public Health Unit areas: Chatham-Kent, Lambton, Middlesex-London, Ottawa, Leeds, Grenville and Lanark, Renfrew County, Simcoe Muskoka, Grey Bruce, and Eastern Ontario.

“Conclusion: Regional variation in the cumulative incidence of six pregnancy complications associated with cardiovascular disease risk was observed in Ontario. Statistically significant clusters of high cumulative incidence of one or more of these pregnancy complications were identified. These regions in particular may benefit from post-partum screening clinics and increased awareness regarding the association between pregnancy complications and cardiovascular disease.”