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Newborns of Asian descent may be misclassified as underweight: study

Babies of East Asian and South Asian descent are more likely to be misclassified as underweight at birth when compared to their Canadian counterparts, according to a study led by St. Michael’s Hospital physician Dr. Joel Ray.

Toronto, May 27, 2009

Dr. Joel Ray Dr. Joel Ray

Babies of East Asian and South Asian descent are more likely to be misclassified as underweight at birth when compared to their Canadian counterparts, according to a study led by St. Michael’s Hospital physician Dr. Joel Ray.

The study demonstrates the need to consider ethnicity before labelling infants as underweight, or "small for gestational age" at birth.

“Birth weight curves currently used in Canada were derived back in 1969, and were based on a small sample of just 300 infants of white European ancestry,” Dr. Ray explained. “While these conventional values have been updated, they do not account for the country’s ever growing variation in ethnicity.”

Dr. Ray and a team of researchers, who developed the first-ever sex-specific birth weight curves for these ethnic groups, studied 5,000 infants born at the hospital between 2002 and 2007. Among this group were 1,565 and 753 babies born of mothers of East Asian and South Asian descent respectively. Birth weight curves were then generated for male and female babies of the ethnic groups. Their study showed between 19 and 34 per 1000 infants born to mothers of East Asian origin and between 80 and 84 per 1000 infants born to mothers of South Asian origin would be miscategorized as small for gestational age at birth.

“We recommend that our curves be tested on more Canadians, and be expanded to other ethnic groups, as well,” said Ray. “More importantly, careful use of these curves should be mandated in their application to infants of mothers of East Asian and South Asian origin.”

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