Birth Outcomes Differ Across Canadian Immigration Categories

Adverse birth outcomes, such as preterm birth and stillbirth, are more likely to occur among refugees in Canada than among economic-class immigrants, according to a new study.

Overall, babies born to Canadian immigrant parents face increased risks for preterm birth, stillbirth, and small size for gestational age (SGA), but these risks vary according to the life experiences of different immigrant groups, the study authors wrote.

“Immigrants are often considered a single, homogeneous group. Scientific research also often focuses on health differences in immigrants versus native-born people,” lead author Seungmi Yang, PhD, associate professor of epidemiology, biostatistics, and occupational health at McGill University in Montreal, Canada, told Medscape Medical News.

“However, immigrants differ in their lived experiences before immigration, their motivations or reasons for immigrating, and their postimmigration environment,” she said. “Since Canada formally accepts immigrants by admission categories with distinct criteria, we thought the admission category would be a meaningful characteristic [by which] to separate immigrants into different groups. And if any important differences were observed, it may help in our creation and provision of healthcare and support programs for immigrants by tailoring to specific subgroups.”

The study was published online on April 2 in CMAJ.

Stillbirths Among Refugees

The investigators conducted a population-based retrospective study, analyzing Statistics Canada data for nearly 8 million Canadian births during the 25 years from 1993 to 2017. The research team looked at the differences in adverse birth and postnatal outcomes for immigrants in the following three categories: Economic-class immigrants (ie, those selected for their skills), family-class immigrants (those who reunified with their families), and refugees. They compared outcomes in these groups with the outcomes of Canadian-born parents. They focused on preterm births, SGA births, large-for-gestational-age (LGA) births, stillbirths, neonatal death within the first month, and overall infant death within the first year.

Among nearly 8 million births, more than 1.7 million (21.5%) were to immigrant mothers. Of the latter births, 50% were to family-class immigrants, 37% to economic-class immigrants, and 13% to refugees.

At the time of birth, immigrants were more frequently married than Canadian-born parents, although refugees were more often unmarried than other immigrants. Refugees were also more likely to have more children, while economic-class immigrants were more likely to be ages 35 years or older at delivery.

Compared with infants of Canadian-born parents, babies in the immigrant groups had higher risks for preterm birth, SGA birth, and stillbirth. They had a lower risk for LGA birth and neonatal death, however.

Compared with infants of economic-class immigrants, babies of refugees had higher risks for preterm birth and LGA birth but lower risk for SGA. On the other hand, infants of family-class immigrants had a higher risk for SGA birth. These trends were most significant for first births among immigrants.

After adjusting for several sociodemographic characteristics, the researchers found that the risks for stillbirth, neonatal death, and overall infant death did not differ significantly among the immigrant groups, although stillbirths were generally higher among refugees. The findings appear to support previous studies that indicate that refugees remain a vulnerable subgroup of immigrants, likely for several reasons, the study authors wrote.

“Differential risks of adverse outcomes between admission categories vary also across outcomes,” Yang said. “Other outcome-specific patterns of differential risks among immigrant subgroups would need to be further examined to better understand the heterogeneity in health experiences among immigrants and potentially reasons for differences.”

Additional factors may contribute to the differential risks for adverse birth outcomes, including socioeconomic challenges, systematic racism, or immigration experiences that have been linked to birth and postnatal outcomes, the study authors wrote.

Immigrants are typically considered healthier than native-born people in their receiving country and tend to be healthier than nonmigrants in their country of origin. This discrepancy is often called the “healthy immigrant effect.” However, information about birth outcomes among immigrants may change this belief and approach to healthcare policy.

‘Arduous Economic Conditions’

Commenting on the study for Medscape Medical News, Marcelo Urquia, PhD, associate professor of community health sciences at the University of Manitoba in Winnipeg, Canada, said, “Immigrants have been shown to possess a health advantage yet are also more likely to reside in arduous economic conditions.”

Urquia, who wasn’t involved with this study, has researched adverse birth outcomes among immigrants, as well as refugee maternal and perinatal health. He and his colleagues found that refugee mothers had higher maternal health risks and more adverse birth outcomes.

“Further research into stressors that refugee mothers experience in their countries of origin, in transition countries, and in countries of resettlement may help support the development of preconception and pregnancy stress prevention and management strategies,” he said. “To help facilitate international comparisons, refugee health researchers may find it useful to state if and how immigration policies shape the health of refugees, relative to other immigrants within their borders.”

The study was supported by the Canadian Institutes of Health Research. Yang and Urquia reported no relevant financial relationships.

Carolyn Crist is a health and medical journalist who reports on the latest studies for Medscape, MDedge, and WebMD.