Introduction:  Mast cells, through the repair of inflammatory mediators, cause structural and functional changes in the female 
reproductive  system;  however,  unregulated  mast  cell  activity  can  lead  to  fertility  problems  in  women.  On  the  other  hand, 
vitamin D, due to its modulatory role on mast cell function, may influence pregnancy success rates.
Methods: The present study is a narrative review conducted using that incorporates observational studies (both descriptive and 
analytical) from the past 25 years (2000–2025).  A total of 53 articles indexed in databases such as SID, Science  Direct, Iran 
medex, Google Scholar, Scopus, and PubMed were reviewed.
Results:  Studies  have  shown  that  vitamin  D,  by  reducing  mast  cell  activity  and  inhibiting  the  production  of  inflammatory 
cytokines, can help improve fertility by decreasing inflammation. Based on the available evidence, vitamin D may be considered
an  inflammatory  a  regulator  of  inflammation  in  reproductive  health.  However,  further  research  is  required  to  completely 
understand the precise mechanisms by which vitamin D affects mast cell activity.
Conclusion:  Given  the  role  of  vitamin  D  in  enhancing  folliculogenesis,  hormonal  regulation,  and  its  anti-inflammatory  and 
antioxidant properties within the ovaries, existing studies suggest that vitamin D treatment may help regulate the number and
activity  of  mast  cells  in  the  endometrium  of  ovulation-induced  mice.  This  regulation  can  prevent  excessive  inflammation, 
improve the uterine environment for embryo implantation, and ultimately increase the success of ovulation and fertility