Prevalence trends of pre- and postnatal depression in Japanese women: A population-based longitudinal study

Background: This study aimed to describe the prevalence trends of pre- and postnatal depression, via measures of the Edinburgh Postnatal Depression Scale (EPDS) total and factor scores, from 20 weeks' gestation to 3 months postpartum, stratified by parity, in a Japanese female population. Methods: A longitudinal, population-based study was conducted among perinatal women giving birth at maternity facilities in Setagaya area of Tokyo, Japan. Of the 1775 women who participated, 1311 women met the inclusion criteria of this analysis. All data, including EPDS, were collected via self-administrated questionnaires at 20 weeks' gestation and at 5 time points postpartum, from the first few days to 3 months postpartum. We divided EPDS items into three factors: anxiety, anhedonia, and depression, according to factor analysis. Results: The prevalence of individuals exhibiting depressive symptoms, EPDS total score, and each factor score peaked at two weeks postpartum in primiparas (EPDS total = 5.58, anhedonia = 0.47, anxiety = 2.64, and depression = 1.23). In contrast, the EPDS total score and factor scores for anxiety and depression gradually decreased for multiparas, from the prenatal to postpartum period (EPDS total 3.33, 3.03, 3.03, 2.72, 2.76, and 2.37). Limitations: Each factor score was not weighted; instead, we simply added up the item scores ranging from 0 to 3 for each question. Additionally, the population representativeness of Japanese women was not high, although the sample was population-based and had a high follow-up rate. Conclusions: This study shows that the trends of EPDS total and factor scores differ by parity throughout the pre- and postnatal periods among a Japanese female population.