Objectives: To comprehensively evaluate and synthesize existing research on the association between vitamin D deficiency and antenatal depression (AD) and post-partum depression (PPD).

Methods: A total of 513 pertinent publications were found after a comprehensive search across four databases. 46 full-text publications were examined after duplicates were eliminated using Rayyan QCRI and relevance was checked; eight studies finally satisfied the requirements for inclusion.

Results: We included eight studies with a total of 5370 pregnant and postpartum women. The prevalence of AD ranged from 4.8% to 90% and the prevalence of PPD ranged from 8.1% to 85.4%. Some studies suggest that higher vitamin D levels, alongside iron, are linked to reduced third-trimester depressive symptoms, indicating a possible protective role of supplementation. However, others found no correlation between vitamin D levels and depression during pregnancy, suggesting that this relationship may be influenced by additional factors. Elevated IL-6 levels have been associated with third-trimester depression, while vitamin D shows an indirect role. Low postpartum vitamin D levels have been connected to an increased risk of postpartum depression, pointing to a potential risk factor. Regional analyses highlight a stronger association of vitamin D deficiency with postpartum than antenatal depression.