Abstract
Objective Postpartum depression often develops within the first few months after delivery, with many cases emerging within four weeks. Although the Edinburgh Postnatal Depression Scale (EPDS) is commonly administered at one month postpartum in Japan, earlier onset highlights the need for earlier screening. This study aimed to examine the relationship between EPDS scores at postpartum day 3 and at one month, and to evaluate the predictive value of early screening. Methods We retrospectively analyzed 559 women who delivered at our hospital between January and December 2021 and attended their one-month postpartum checkup. EPDS was administered to all participants on postpartum day 3 and at one month postpartum. A cutoff of ≥9 points was used to define positivity. Correlation was assessed using Spearman's test, and receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff score on day 3 for predicting positivity at one month. Results At one month postpartum, 41 women (7.3%) were EPDS-positive. On postpartum day 3, 131 women (23.4%) were positive, of whom 22 (16.8%) remained positive at one month. Among 428 women negative at day 3, 19 (4.4%) converted to positive at one month. EPDS scores on day 3 were significantly correlated with those at one month (r = 0.476, p < 0.001). ROC analysis identified 5 points as the optimal cutoff on day 3 for predicting positivity at one month. Conclusion EPDS scores at postpartum day 3 are significantly correlated with those at one month and may help identify women at risk for postpartum depression earlier than the conventional one-month screening. Even women scoring 5-8 points at day 3, though below the traditional cutoff, showed an increased risk of later conversion and warrant careful follow-up and supportive interventions.