Objective: To examine the association between maternal country of birth and the risk of preeclampsia+preterm birth (PTB).
Study design: We completed a population-based study in the entire province of Ontario, where there is universal access to obstetrical care. We included 881 700 singleton livebirths among Canadian-born mothers and 305 547 births among immigrant mothers. Adjusted risk ratios (aRRs) were adjusted for maternal age, parity and income quintile.
Results: Compared with a rate of preeclampsia+PTB of 4.0 per 1000 among Canadian-born mothers, the aRR of preeclampsia+PTB at 24 to 36 weeks was significantly higher for immigrant women from Nigeria (1.79, 95% confidence interval (CI) 1.12 to 2.84), the Philippines (1.54, 95% CI 1.30 to 1.86), Colombia (1.68, 95% CI 1.04 to 2.73), Jamaica (2.06, 95% CI 1.66 to 2.57) and Ghana (2.12, 95% CI 1.40 to 3.21). The aRRs generally followed a similar pattern for secondary outcomes. Specifically, women from Ghana were at highest risk of preeclampsia+very PTB (4.55, 95% CI 2.57 to 8.06), and women from Jamaica at the highest risk of preeclampsia+indicated PTB (1.89, 95% CI 1.43 to 2.50).
Conclusion: The risk of preeclampsia+PTB is highest among women from a select number of countries. This information can enhance initiatives aimed at reducing the risk of PTB related to preeclampsia.