Prevalence of postpartum depressive symptoms in a multiethnic population and the role of ethnicity and integration

•Prevalence rate of postpartum depressive symptoms was 9.3% for the whole study sample.•Prevalence rate was 4.8% for Western European women and 12.7% for the ethnic minorities.•In contrast to minority women, majority of the Western European women with postpartum depressive symptoms also had depressive symptoms during pregnancy.•Ethnic minority background and low social integration were independent risk factor for postpartum depressive symptoms.•Recent adverse life events, lack of social support and depressive symptoms in the index pregnancy were also significant risk factors for postpartum depressive symptoms. Postpartum depression (PPD) may have adverse effects on both mother and child. The aims were to determine the prevalence of postpartum depressive symptoms, PPDS, identify associations with ethnicity and with the level of social integration. Population-based, prospective cohort study of 643 pregnant women (58% ethnic minorities) attending primary antenatal care in Oslo. Questionnaires regarding demographics and health issues were collected through interviews. PPDS was defined as a sum score ≥ 10 by the Edinburgh Postnatal Depression Scale, used as the main outcome in logistic regression analyses, first with ethnicity, second with level of integration as main explanatory factors. The prevalence of PPDS was higher in ethnic minorities 12.7% (95% CI: 9.31–16.09) than in Western Europeans 4.8% (2.26–7.34). Adverse life events, lack of social support and depressive symptoms during the index pregnancy were other significant risk factors. Western European with PPDS were more likely to have had depressive symptoms also during pregnancy than women from ethnic minorities (72.2% versus 33.3%, p = 0.041). When replacing ethnicity with integration, a low level of integration was independently associated with PPDS (2.1 (1.11–3.95)). Cases with PPDS were limited. Heterogeneity in the ethnic groups is a concern. Both point prevalence and new onset of PPDS was higher among ethnic minorities than among Western Europeans. Low level of integration was associated with PPDS. Our findings suggest that clinicians should be aware of the increased risk of new cases of PPDS among ethnic minorities compared to Western European women and offer evidence-based care accordingly.