Effect of adopting host-country nationality on perinatal mortality rates and causes among immigrants in Brussels

ObjectivesPerinatal mortality rates vary between ethnic groups but the relation with immigrant status is unclear. Previous research suggested that birth outcomes may either improve or deteriorate with duration of residence, depending on the migrant group. The objectives of this study are to describe and measure inequalities in pregnancy outcomes, perinatal mortality and causes of perinatal deaths according to current citizenship versus national origin of the mother, in Brussels.Study designThis is a population-based cohort study using data from linked birth and death certificates from the Belgian civil registration system. The data relate to all babies born between 1998 and 2008, whose mothers were living in Brussels, irrespective of the place of delivery. We used a logistic regression to estimate the odds ratios (ORs) for the association between mortality, causes of deaths and nationality.ResultsWomen from Morocco, sub-Saharan Africa and Turkey experience an 80% excess in perinatal mortality (p < 0.0001) compared to Belgians, but this excess of perinatal mortality is not observed for mothers with Belgian citizenship at delivery. For sub-Saharan African women, this excess is caused mainly by immaturity-related conditions and reflects a high rate of preterm deliveries, low birth weight and a low socio-economic level. Moroccan and Turkish mothers have favourable pregnancy outcomes that persist after adopting Belgian nationality, but they experience a strong excess of perinatal mortality, mainly due to congenital anomalies and asphyxia or unexplained deaths prior to the onset of labour.ConclusionIn Brussels, perinatal mortality varies according to nationality but those differences do not persist after adopting Belgian nationality. The explanation of this positive effect is probably due to a mix of determinants such as acculturation, use of health services or cultural contexts. Further analysis should help to better understand the results observed.