Objective
Approximately 6 to 13% of women suffer from antenatal depression (AD) around the world. AD can lead to several health problems for mother-baby. Vitamin D is a molecule that appears to have great preventive/therapeutic potential against neuropsychiatric disorders. The present study aimed to analyze the association between deficiency of vitamin D and AD in pregnant women in a city in the south of Brazil (Pelotas, RS). We hypothesize that pregnant women with a positive AD diagnosis have deficient levels of 25-hydroxyvitamin D (25(OH)D).

Methods
This cross-sectional study was conducted in a cohort study (CEP/UCPEL 47807915.4.0000.5339). From this cohort, 180 pregnant women at up to 24 weeks gestation were selected (130 non-depressed and 50 depressed), and the diagnosis of depression was made using the MINI-Plus. Blood was collected and stored for the later analysis of vitamin D (25(OH)D) by chemiluminescence method. The SPSS program was used for data analysis, and p<0.05 was considered statistically significant.

Results
In our study, we showed a significant association between Major Depressive Episode current in the antenatal period and vitamin D deficiency (OR: 0.9; CI 95%: 0.9;1.0, p=0.003).

Conclusion
Our results demonstrate that vitamin D deficiency may be involved in major depressive disorder in the antenatal period, in this way it advised a follow-up of vitamin D levels in the pregnancy-puerperal cycle to minimize mental health problems in women and prevent developmental deficits in children.