Investigation of the relationship between salivary nitrate levels and perinatal anxiety and postpartum depression.

BACKGROUND

Postpartum depression (PPD) is a common psychological condition affecting 10-20% of postpartum women, characterized by emotional instability, anxiety, and, in severe cases, hallucinations or suicidal ideation. Growing evidence suggests a link between oxidative stress and depression, with nitrite-a key metabolite of nitric oxide (NO)-emerging as a potential biomarker. This study explores the association between salivary nitrite levels, perinatal anxiety, and PPD, aiming to identify predictive factors for early intervention.

METHODS

A prospective clinical study was conducted involving 220 naturally delivered women. Saliva samples were collected at three time points: before labor analgesia, one hour post-analgesia, and on the discharge day. PPD was assessed using the Edinburgh Postnatal Depression Scale (EPDS) at 28 and 42 days postpartum. Logistic regression was applied to analyze the relationship between salivary nitrite levels and PPD risk (EPDS ≥ 9). Anxiety, information needs, and fear were evaluated as additional predictors.

RESULTS

Of 220 participants, 194 completed the study. The incidence of PPD was 10.82% at 28 days and 15.98% at 42 days postpartum. Higher pre-analgesia salivary nitrite levels were significantly associated with increased PPD risk at 28 days (OR = 1.017,  < 0.05) and 42 days (OR = 1.008,  < 0.05), with a stronger effect at 28 days. Preoperative anxiety was a strong predictor at 28 days (OR = 1.76,  = 0.019), while preoperative information needs were significant at 42 days (OR = 1.22,  = 0.043). Salivary nitrite levels significantly decreased after labor analgesia and remained low at discharge.

CONCLUSION

This study is the first to demonstrate a significant association between salivary nitrite levels and the occurrence of postpartum depression (PPD), with this association being particularly pronounced at 28 days postpartum. Perinatal anxiety and information needs were also identified as important predictors of PPD. This research provides a new perspective for the early screening and intervention of PPD and points the way for future studies to further explore its mechanisms and predictive factors.