Maternal and paternal birthplace and risk of stillbirth

To evaluate the influence of maternal and paternal country of origin on stillbirth risk.

We conducted a retrospective case-control study of all deliveries in Ontario between 2002 and 2011. We included 1373 stillbirths and 1 166 097 live births that had a documented country of origin for both parents. All newborns were singleton, born at between 20 and 42 weeks' gestation, and weighed 250 g to 7000 g. We computed adjusted odds ratios (aOR) and 95% confidence intervals for the risk of stillbirth associated with parental country of origin. Models were adjusted for infant sex, maternal age, parity, marital status, and residential income quintile.

Compared with parent pairs in which both parents were Canadian-born, the aOR of stillbirth was higher whether immigrant parents came from the same country (aOR 1.32, 95% CI 1.16 to 1.51) or from different countries (aOR 1.34, 95% CI 1.08 to 1.65). The risk of stillbirth was highest for immigrant parents coming from the same country if that country had a high domestic stillbirth rate (aOR 1.60, 95% CI 1.30 to 1.97).

Maternal and paternal country of origin influences stillbirth risk. Foreign-born couples, especially those originating from a country with a high stillbirth rate, are at greater risk. Attention should focus on identifying genetic and environmental risk factors for stillbirth among specific immigrant groups, including developing prevention strategies for high-risk couples.