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Recent immigrants to Ontario have less pregnancy complications


Women who recently immigrated to Ontario may have a lower risk of certain pregnancy complications compared with women who have been living in the province longer, a new study from Institute for Clinical Evaluative Sciences (ICES) and St. Michael’s Hospital has found.

“Persons who immigrate to Western countries are believed to experience fewer chronic health problems than domestically-born individuals – the so-called ‘healthy immigrant effect’,” said Dr. Joel Ray, a clinician scientist at St. Michael’s Hospital and the University of Toronto.

“However, prior research has been principally restricted to the study of chronic conditions, and a woman’s duration of residency in her adopted country has not been evaluated in relation to pregnancy.”

To study this issue further, investigators tracked over 796,000 women who were either native-born Ontario residents or landed immigrants to Ontario, and who had a first documented obstetrical delivery between 1995 and 2005. Recency of immigration was defined by each woman’s date of enrollment in the Ontario Health Insurance Plan (OHIP), prior to her date of delivery, which ranged from under three months to five years or more.

Among these women, the development of a maternal placental syndrome (MPS) – defined as a composite of pre-eclampsia (new-onset hypertension in pregnancy after 20 weeks gestational age, in association with protein in the urine), placental abruption (the premature separation of the placenta from the uterine wall) or placental infarction (blockage of blood circulation to a localized area of the placenta) – was evaluated.

Overall, MPS occurred in 5.7% of women. The risk of MPS was lowest among those who had immigrated within three months before delivery (3.8%) and highest in women living in Ontario at least five years (6.0%).

“Our results suggest that we need to preserve the apparent healthier state of new immigrant women through policies designed to discourage the adoption of adverse lifestyle choices,” said Dr. Ray.

“For long-term immigrants and native-born residents, the goal should be to improve their health status. Common to all should be consideration of the prevention of obesity and the optimization of nutrition prior to pregnancy, especially in childhood, adolescence and early adulthood, since obesity is a risk factor for MPS. This approach may also translate into long-term health benefits for women at high-risk, regardless of immigration status or pregnancy outcome.”

The study, “Results of the Recent Immigrant Pregnancy and Perinatal Long-term Evaluation Study (RIPPLES)”, is in the May 8, 2007 issue of the Canadian Medical Association Journal (CMAJ).

Author affiliations: ICES (Drs. Schull and Redelmeier, and Ms. Vermeulen); Department of Medicine (Drs. Ray, Schull and Redelmeier), and Health Policy, Management and Evaluation (Drs. Ray, Schull and Redelmeier), University of Toronto; Department of Obstetrics and Gynecology (Drs. Ray, Shah and Singh), and Centre for Research on Inner City Health (Dr. Singh), St. Michael’s Hospital; Sunnybrook Health Sciences Centre (Drs. Schull and Redelmeier)

ICES is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy.


  • Julie Dowdie
  • Media Relations Officer, ICES
  • (416) 480-4780 or cell (416) 432-8143

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