Abstract

Background

International migration is the main source of population growth in Canada. Research on the birth outcomes of immigrants has largely been based on Canadian provincial data, raising concerns about whether the findings can be generalized between provinces or between the provinces and Canada. Provincial time trends and variations in birth outcomes are described according to the 20 top maternal birthplaces.

Data and methods

Statistics Canada’s Vital Statistics–Birth Database (2000 to 2016) was used to extract 5,831,580 records on live births for analyses. Rates of preterm birth (PTB, referring to births at 22 to 36 gestation weeks) and mean birth weight (at 39 to 40 gestation weeks) were compared across provinces between immigrant mothers, according to the top 20 maternal birthplaces, and Canadian-born mothers.

Results

The proportion of births to immigrant mothers rose overall from 23.7% in 2000 to 30.7% in 2016, but rose unevenly across the provinces. Increases were modest in British Columbia and Ontario; twofold in Alberta, Manitoba and Quebec; and fourfold in Saskatchewan. Compared with PTB rates among Canadian-born mothers, PTB rates were lower among various Asian, African and Western immigrant groups and higher among those from Bangladesh, the Philippines and the Caribbean. Lower birth weights were seen for most source countries, except the United States. These differences were uniform across the provinces, with a few exceptions.

Interpretation

There were large provincial variations in the proportion of births to immigrant mothers. However, disparities in birth outcomes did not substantially vary across provinces for most immigrant maternal birthplaces, suggesting some degree of generalizability for provincial birth data.

Keywords

Canada, perinatal, foreign-born, immigrants, preterm birth, birth weight

DOI: https://www.doi.org/10.25318/82-003-x202000400002-eng

Findings

In Canada, information on birth outcomes is routinely collected at the provincial and national levels through birth registrations and hospital records. These data are useful to understand perinatal health at the population level and its variations according to key sociodemographic characteristics, such as immigration status. Immigration is the main source of population growth in Canada; together, immigrants and second-generation individuals are projected to account for 1 out of 2 people by 2036. Studies on differences in perinatal outcomes between immigrant groups and non-immigrants have provided conflicting results, mainly because of the heterogeneity of study populations, data sources and analytic approaches. The perinatal health of infants born in Canada to immigrant mothers has primarily been studied using linked population-based provincial databases, and, more recently, using national data. Based on the level of geography results are presented at, there are concerns about the generalizability of results from province to province, from a particular province to the national level, and from the national level to the provincial level. For a single immigrant group, differences in birth outcomes may exist between Canadian provinces because of selection factors (e.g., provincial immigration programs and language), different post-migration experiences, or a combination of the two. Little is known about whether observed associations between maternal birthplace and birth outcomes are consistent across provinces. [Full article]

Authors

Janelle Boram Lee, Aynslie Hinds and Marcelo L. Urquia are with the Manitoba Centre for Health Policy in Winnipeg, Manitoba. Janelle Boram Lee and Marcelo L. Urquia are also with the Community Health Sciences Department at the University of Manitoba; Aynslie Hinds is also with the Institute of Urban Studies at the University of Winnipeg.

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What is already known on this subject?

  • Studies on differences in perinatal outcomes between immigrant groups and non-immigrants provide conflicting results because of the heterogeneity of study populations and methodological approaches.
  • Little is known about the comparability of birth outcomes of immigrants across Canadian provinces.

What does this study add?

  • A single national dataset was used to compare provincial temporal trends and disparities in birth outcomes according to maternal birthplace, thereby overcoming problems associated with the heterogeneity of data sources and methodological approaches.
  • The proportion of births to immigrants reached 30% in 2016 for the first time in Canada, but occurred unevenly across the provinces.
  • Disparities in PTB rates between immigrant and non-immigrant groups were moderate, with some variations between provinces. However, disparities in birth weight were large and had a similar direction and magnitude across provinces for most immigrant groups.
  • Deviations from the national pattern may reflect province-specific immigration dynamics.

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