Objective To determine if immigrant women from low-, middleand high-income countries have an increased risk of severe maternal morbidity (near-miss) when they deliver in Sweden.Design Population register-based study.Setting Nationwide study including all singleton deliveries (≥28 weeks of gestation) between 1998 and 2007.Population Women with a near-miss event; all women with a singleton delivery ≥28 weeks of gestation during the same period acted as reference group.Methods Near-miss was defined by a combined clinical and management approach with use of International Classification of Diseases, 10th revision codes for severe maternal morbidity. A woman's country of origin was designated as low-, middle-or high-income according to the World Bank Classification of 2009. Unconditional logistic regression models were used in the analysis.Main outcome measures Maternal near-miss frequencies per 1000 deliveries and odds ratios with 95% confidence intervals.Results There were 914 474 deliveries during the study period and 2655 near-misses (2.9 per 1000 deliveries). In comparison to Swedish-born women, those from low-income countries had an increased risk of near-miss (odds ratio 2.3, 95% confidence interval 1.9-2.8) that was significant in all morbidity groups except for cardiovascular diseases and sepsis. Women from middle-and high-income countries showed no increased risk of near-miss.Conclusions Women from low-income countries have an increased risk of maternal near-miss morbidity compared with women born in Sweden. Although the rate is low it should alert healthcare providers.Keywords Immigration, maternal near-miss, severe maternal morbidity.Please cite this paper as: Wahlberg Å , R€ o€ ost M, Haglund B, H€ ogberg U, Ess en B. Increased risk of severe maternal morbidity (near-miss) among immigrant women in Sweden: a population register-based study.