Background: Understanding and tackling perinatal health inequities in industrialized countries requires analysing the socioeconomic determinants of adverse pregnancy outcomes among immigrant populations. Studies show that among certain migrant groups, education is not associated with adverse pregnancy outcomes. We aim to extend this analysis to further dimensions of socioeconomic status (SES) and to other settings. The objective of this study is to identify sociodemographic characteristics associated with adverse pregnancy outcomes, according to the origin of mothers residing in Brussels. Methods: We analysed all singleton live births in Brussels between 2005 and 2010 (n = 97,844). The data arise from the linkage between three administrative databases. Four groups of women were included according to their place of birth: Belgium, EU, North Africa, and Sub-Saharan Africa. For each group, logistic regression was carried out to estimate the odds ratios of low birthweight (LBW) and small for gestational age (SGA) according to SES indicators (household income, maternal employment status, maternal education) and single parenthood. Results: Three key findings emerge from this study: 1) 25% of children were born into a household under the poverty threshold. This proportion was much higher for mothers born outside of the EU. 2) For North African immigrants, SES indicators didn't influence the pregnancy outcomes, whereas their risk of LBW increased with single parenthood. 3) For Sub-Saharan Africans the risk of LBW increased with low household income. Conclusion: In a region where immigrant mothers are at high poverty risk, we observe a classic social gradient in perinatal outcomes only for mothers born in Belgium or the EU. In the other groups, SES influences perinatal outcomes less systematically. To develop interventions to reduce inequities from birth, it's important to identify the determinants of perinatal health among immigrants and to understand the underlying mechanisms in different contexts. © 2018 The Author(s).

health inequalities Socioeconomic status immigrants Perinatal health Adverse birth outcomes poverty

educational status immigrant Africa south of the Sahara Registries poverty health disparity Health Status Disparities register human Ethnic Groups statistics and numerical data ethnic group ethnology Humans migrant Infant, Newborn male Emigrants and Immigrants female risk factor Risk Factors newborn Africa socioeconomics pregnancy Mothers Belgium European Union Article low birth weight pregnancy outcome employment status mother adult household income Africa, Northern single parent small for date infant North Africa social class