Postnatal depressive symptoms display marked similarities across continents.

BACKGROUND: Postnatal depressive symptoms measured by the Edinburgh Postnatal Depression Scale (EPDS) are reported to display measurement variance regarding factor structure and the frequency of specific depressive symptoms. However, postnatal depressive symptoms measured by EPDS have not been compared between women representing three continents. METHODS: A cross-sectional study including birth cohort samples from Denmark, Vietnam and Tanzania. Women were included during pregnancy at routine care sites. Depressive symptoms were self-reported 40-90 days postpartum using the EPDS. Exploratory and confirmatory factor analyses and generalized additive regression models were performed. RESULTS: A total of N = 4,516 participated in the study (Denmark N = 2,069, Vietnam N = 1,278, Tanzania N = 1,169). Factor analyses identified three factors (anhedonia, anxiety and depression) that were almost identical in the three study populations. The only variation between countries was that the item 'self-harm' loaded differently. Women from Tanzania and Denmark were more likely to have an EPDS total score above cut-off 12 (12.6% and 6.4%), compared to women from Vietnam (1.9%) (p<0.001). A low level of education was associated with significantly more depressive symptoms after adjusting for country (p<0.001). LIMITATIONS: EPDS data was collected at a later time point in the Danish sample. CONCLUSIONS: Postnatal depressive symptoms constitute a three-factor model across cultures including the factors anhedonia, anxiety and depression. The frequency of postnatal depressive symptoms differs between high-, medium-, and low-income countries. However, clinicians should bear in mind that low-educated women worldwide are more likely to experience postnatal depressive symptoms.