Association between birth memory and postpartum psychological distress: The mediating role of sleep quality

Birth memory has been associated with postpartum psychological distress, particularly postpartum depression (PPD) and childbirth-related post-traumatic stress disorder (CB-PTSD). However, the mechanisms underlying this relationship remain poorly understood. Poor sleep quality has been associated with both negative autobiographical memories and increased risk of psychological distress, suggesting it may mediate this relationship.

To investigate the mediating role of sleep quality in the relationship between birth memory and postpartum psychological distress.

This cross-sectional study recruited primiparous women aged 18 to 49 years who had a vaginal birth and had a child aged 1 to 3 months from two tertiary-level public hospitals in China, between September and December 2024. A total of 420 women participated. Birth memory was measured using the 21-item Birth Memory and Recall Questionnaire. Postpartum psychological distress, operationally defined as the presence of PPD and/or CB-PTSD, was measured using the 10-item Edinburgh Postnatal Depression Scale and the 14-item Perinatal Posttraumatic Stress Disorder Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Mediation analysis was used to estimate the total natural indirect effect (TNIE), pure natural direct effect, total effect, and proportion mediated. Sensitivity analyses were conducted to assess the robustness of TNIEs against unmeasured confounding.

Five dimensions of birth memory: 1. emotional memory, 2. reliving, 3. centrality of memory, 4. sensory memory, and 5. involuntary recall indirectly increased the risk of postpartum psychological distress through impaired sleep quality, with TNIE odds ratios ranging from 1.09 to 1.12 (all P < 0.05). The proportion mediated ranged from 0.25 to 0.34 (all P < 0.05). Sensitivity analyses confirmed the robustness of the TNIEs with respect to the potential effects of unmeasured confounding. Coherence of memory did not show a significant TNIE on postpartum psychological distress through sleep quality (P = 0.441).

Sleep quality partially mediates the relationship between specific dimensions of birth memories and postpartum psychological distress. These findings highlight the importance of sleep interventions in the postpartum period, particularly for women with negative birth experiences, as a potential strategy for preventing or alleviating postpartum psychological distress.