Perinatal health outcomes in relation to principal applicant and live-in caregiver status among economic class immigrants to Canada: A retrospective analysis of births from 1993 to 2017

Objectives Economic class immigrants to Canada tend to have better health outcomes than other immigrant groups. However, variation may exist even within this population. Methods We conducted a retrospective cohort analysis of data from the Migrant Maternal and Infant Morbidity and Mortality (MMIMM) dataset, which linked Canadian birth and infant death records (1993–2017) with maternal immigration records (1952–2017). All singleton births to economic class immigrant women at least 18 years of age at immigration were analyzed. Women were classified as principal applicants (PA), non-principal applicants (NPA), or former live-in caregivers (LIC); all analyses were stratified by marital status at landing. Outcomes examined included preterm birth (PTB), small- and large-for-gestational-age birth (SGA and LGA, respectively), stillbirth, and infant mortality. Risk ratios for adverse outcomes by PA and former LIC status were estimated with adjustment for parental, birth, and immigration characteristics. Results The cohort included 490,310 births (165,850 births to PAs, 267,200 to NPAs, 57,160 to former LICs). In adjusted analyses, among women who were single at landing, NPA had slightly lower rates of LGA (fully adjusted risk ratio (aRR) = 0.92, 95% CI 0.87–0.98) and stillbirth (aRR = 0.72, 95% CI 0.53–0.97) compared to PA, and former LICs had slightly elevated rates of PTB (aRR 1.05, 95% CI 1.00–1.11) and SGA (1.05, 95% CI 1.01–1.10). Conclusion These findings add to existing literature highlighting the vulnerability of live-in caregivers in Canada while shedding light on possible differences between principal and non-principal applicants.