Association of immune-inflammatory biomarkers during pregnancy and the postpartum period with postpartum depression symptoms: A cross-sectional and longitudinal retrospective analysis

Abstract

Background

Postpartum depression (PPD) is characterized by feelings of sadness, hopelessness, and disinterest in daily activities, leading to detrimental effects on both maternal and child well-being. We aimed to investigate the associations between blood immune-inflammatory biomarkers during pregnancy and the postpartum period and the risk of PPD.

Methods

In this study, we included postpartum women who underwent routine blood tests during second and third trimester visits as well as postpartum reviews. Immune-inflammatory biomarkers were assessed at three time points: neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammatory index (SII), systemic inflammatory response index (SIRI), and pan-immune-inflammatory value (PIV). PPD symptoms were assessed at five to eight weeks postpartum using the Edinburgh Postnatal Depression Scale (EPDS). Multivariable logistic regression, restricted cubic spline (RCS) regression, and subgroup and sensitivity analyses were used to examine the relationships between immune-inflammatory biomarkers and PPD symptoms.

Results

Of the 17,500 women eligible for analysis, 2,576 (14.72 %) exhibited PPD symptoms. During the postpartum period, maternal lymphocyte count was associated with decreased odds of PPD symptoms (OR = 0.86, 95 % CI: [0.80, 0.93]), whereas NLR, PLR, and SII were associated with increased odds of PPD symptoms after Bonferroni correction (OR = 1.19, 95 % CI: [1.06, 1.34]; OR = 1.40, 95 % CI: [1.21, 1.61]; OR = 1.18, 95 % CI: [1.07, 1.30], respectively). The relationships showed significant linear trends (all P for nonlinear > 0.05). Subgroup analyses demonstrated that cesarean delivery could modify the association between NLR and PPD symptoms (P for interaction = 0.034). The significant association between NLR and PPD symptoms was observed only in women without cesarean delivery (OR = 1.31, 95 % CI: [1.13, 1.52]). Sensitivity analyses showed that the main findings remained robust.

Conclusions

Our findings suggest that lymphocyte count, NLR, PLR, and SII during the postpartum period are independent risk factors for PPD symptoms. Monitoring these biomarkers could aid in clinical decision-making and the implementation of effective PPD management strategies.