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Socioeconomic disparities in birth outcomes

Released: 2017-11-15

In recent years in Canada, about 9% of babies born are small for their gestational age (SGA) and 8% are born preterm. Given that these babies are at increased risk of infant illness or death, and at increased risk of health problems in later life, it is important to understand the factors that might contribute to these birth outcomes.

Socioeconomic factors, for example, have been associated with increased risk of SGA birth and preterm birth. A new study released today in Health Reports examines the impact of maternal education and income on SGA births and preterm births in Canada, based on a new dataset that links birth data with census results.

The study finds that both SGA birth and preterm birth were associated with maternal education, while SGA birth was also associated with income adequacy. When factors including age, ethnicity and marital status were taken into account, mothers whose highest level of education was high school graduation were 17% more likely to experience an SGA birth and 24% more likely to experience a preterm birth, compared with mothers with a university degree. At the same time, mothers in the lowest income quintile were 22% more likely than mothers in the highest quintile to experience an SGA birth.

  Note to readers

Annual rates of small-for-gestational-age birth and preterm birth are based on data from the Vital Statistics—Birth Database.

The analysis for this study pertains to the 2006 Canadian Birth—Census Cohort, a cohort of singleton births (from May 2004 through May 2006) that was created by linking the Canadian Live Birth, Infant Death and Stillbirth Database to results from the 2006 Census.

The perinatal outcomes were: small-for-gestational-age birth (sex-specific birth weight below the 10th percentile for gestational age, based on the Canadian reference) and preterm birth (before 37 weeks of completed gestation).

The same dataset was employed in a second study in Health Reports that compares birth outcomes among First Nations, Inuit and Métis women.


"Socioeconomic disparities in small-for-gestational-age birth and preterm birth" is available in the November 2017 online issue of Health Reports, Vol. 28, no. 11 (Catalogue number82-003-X).

This issue of Health Reports also contains the article "Birth outcomes among First Nations, Inuit and Métis populations."

Contact information

To enquire about "Socioeconomic disparities in small-for-gestational-age birth and preterm birth," contact Michael Tjepkema (, Health Analysis Division.

To enquire about the concepts, methods or data quality of "Birth outcomes among First Nations, Inuit and Métis populations," contact Amanda Sheppard (, Cancer Care Ontario.

For more information, or to enquire about the concepts, methods or data quality of this release, contact us (toll-free 1-800-263-1136; 514-283-8300;

For more information about Health Reports, contact Janice Felman (613-799-7746;, Health Analysis Division.

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