BACKGROUND: Using labor, epidural analgesia has been linked to a reduced risk of postpartum depression, but the role of labor pain relief in this association remains unclear. The goal of this study was to test the hypothesis that effective epidural analgesia during labor is associated with reduced postpartum depression symptomatology.
METHODS: A single, institutional, retrospective, observational cohort design was chosen. The primary outcome was Edinburgh postnatal depression scale (EPDS) score, measured at the 6-week postpartum visit. Subjects included in the final analysis had (1) received labor epidural analgesia; (2) pain assessed during labor both before and during initiation of labor epidural analgesia by 0–10 numeric rating scores; and (3) depression risk assessed by the EPDS and documented at their 6-week postpartum visit. Simple and multiple linear regression was used to identify the best model for assessing the association between pain improvement, defined as percent improvement in pain (PIP), and depression, after adjusting for a history of anxiety or depression, other psychiatric history, abuse, trauma, mode of delivery, and other maternal or fetal comorbid diseases.
RESULTS: Two hundred one patients were included in the final analysis. Women with higher improvements in pain were associated with lower EPDS scores (r = 0.025; P = .002). Variables known to be associated with depression (body mass index, anxiety and/or depression, third- and fourth-degree perineal lacerations, and anemia) were significantly correlated with EPDS score and included in the final model. After we adjusted for these covariates, PIP remained a significant predictor of EPDS score (r = 0.49; P = .008), accounting for 6.6% of the variability in postpartum depression scores. The full model including pain, body mass index, anxiety and/or depression, perineal lacerations, and anemia explained 24% of the variability in postpartum depression scores.
CONCLUSIONS: Although the extent of labor pain relief by epidural analgesia predicts lower postpartum depression scores, the relative contribution of PIP to risk for postpartum depression symptoms may be less than other established risk factors for depression. These data support that the clinical significance of labor analgesia in the development of postpartum depression needs to be more clearly defined.