Postpartum loneliness predicts future depressive symptoms: a nationwide Japanese longitudinal study

Purpose The COVID-19 pandemic has intensified feelings of loneliness, especially among postpartum women. This nationwide Japanese longitudinal study assessed the impact of such feelings on depressive symptoms and mother-to-infant bonding difficulties (MIBD), two pivotal determinants of maternal and infant well-being. Methods Starting with a baseline survey conducted between July and August 2021, we tracked 1254 postpartum Japanese women who initially reported minimal depressive symptoms (i.e., Edinburgh Postnatal Depression Scale < 9) and MIBD (i.e., Mother-to-Infant Bonding Scale < 5), over a follow-up period of approximately 6 months. Baseline loneliness was evaluated with the UCLA Loneliness Scale Short-Form (UCLA-LS3-SF3). Results Forty-nine percent of the sample reported the presence of baseline feelings of loneliness. After propensity score matching on sociodemographics and various pregnancy, childbirth, and COVID-19–related aspects, baseline loneliness was associated with increased risks of later depressive symptoms but not MIBD. Using restricted cubic spline logistic regression and considering loneliness as a continuous variable, we found a positive increasing quadratic relationship with depressive symptoms. As loneliness increased, so did the risk of later depressive symptoms. However, there was no significant association between loneliness and MIBD. These results were confirmed through a sensitivity analysis using inverse probability weighting to address attrition bias. Conclusion Feelings of postpartum loneliness are associated with future risks of depressive symptoms. The data suggests that addressing loneliness in postpartum women early is crucial to safeguarding their well-being and that of their infants.