Received January 12, 2021
Accepted July 29, 2021

Objective: This current survey investigated the role of the Forkhead 3 box protein (foxp3) gene and serum vitamin D level in women with recurrent spontaneous abortion (RSA). Methods: The mRNA level of the foxp3 gene in peripheral blood was evaluated in women with a history of RSA (N=40) to the controls (N=40) via the quantitative polymerase chain reaction. We employed the enzyme-linked immunosorbent assay to assay the serum concentration of 1,25-dihydroxyvitamin D3 (1,25(OH)2 D) in both groups. The statistical analysis was performed by using the U-Mann-Whitney test the Pearson correlation coefficient between and within the study groups, respectively. Results: Although the mRNA levels of foxp3 were higher in the women with RSA than in the controls, we observed no significant change in mRNA levels of foxp3 between the two groups (P =0.16). An important positive correlation was observed between the foxp3 mRNA levels and 1,25(OH)2 D in controls (P = 0.003). In contrast, the correlation between the foxp3 expression and 1,25(OH)2 D was not significant in the case group (P = 0.14). The concentration of vitamin D serum was lower in the women with RSA than the controls (P <0.001). Conclusions: Our findings demonstrated 1,25Vitamin D3 along with other molecules could act to prevent RSA by providing requirements for the anti-inflammatory state not necessarily through foxp3 expression and T cell differentiation.