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Parents’ country of origin influences risk of stillbirth

Toronto, April 14, 2015

By Melissa Di Costanzo

Dr. Joel Ray
Dr. Joel Ray

Parents’ country of origin influences the risk of their baby being stillborn in Canada, a new study has found. The risk is highest when both parents migrated to Canada from the same country of origin, especially from a country with a high rate of stillbirths, said Dr. Joel Ray, a physician at St. Michael’s Hospital and scientist in its Li Ka Shing Knowledge Institute. This risk is compared to a pregnancy where both parents are born in Canada, and takes into account a mother’s age, marital status and income level.

One explanation for the higher risk of stillbirth may be related to genetic factors that are heightened when a couple of the same ethnicity have a child, said Dr. Ray, whose findings were published online today in the Journal of Obstetrics and Gynecology Canada.

However, even couples from different countries had a higher risk of stillbirth than parents who were both Canadian-born, which suggests that genetic factors alone cannot explain the higher risk. Moreover, when one parent was Canadian-born and the other foreign-born, Dr. Ray and his colleagues found the risk of stillbirth to be similar to that for fetuses of Canadian-born couples.

The risk of stillbirth was highest when both parents came from Nigeria, Portugal, Jamaica, and Guyana, the study found.

According to the World Health Organization, roughly 2.6 million stillbirths occurred worldwide in 2009. In Ontario, about 1 in 200 viable pregnancies ends in stillbirth, a number that, according to Dr. Ray, is still too high.

“Parents who experience stillbirths face devastating emotional consequences,” said Dr. Ray. “It’s time policy-makers turn their attention to developing prevention strategies for couples identified as high risk.” He said that identifying environmental risk factors should also be further probed.

Dr. Ray said the study also examined both maternal and paternal risk factors. Research already points to a variety of maternal risk factors for stillbirth, including obesity, smoking, diabetes, hypertension, unemployment, low education, ethnicity and immigration status. Paternal risk factors, however, have been less explored. It’s important to consider both, said Dr. Ray, as the genetic code from the father – not just the mother – may contribute to the growth and wellbeing of the fetus.

The study used data from all deliveries in Ontario from 2002 and 2011. More than 1.1 million births with parents’ documented country of origin were analyzed. All were born at 20-42 weeks’ gestation.

The study was funded by the Canadian Institutes of Health Research.

About St. Michael's Hospital

St. Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future health care professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael's Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.