Vitamin D and benign gynaecological diseases: a critical analysis of the current evidence.

Vitamin D is a fat-soluble pro-hormone that plays an important role in bone homeostasis; beside this principal function, vitamin D promotes modulation of cell growth, neuromuscular and immune function, and reduction of inflammation. In addition, several in vitro and in vivo studies have demonstrated that vitamin D deficiency could increase the risk of cancer, autoimmune and cardiovascular diseases. Moreover, vitamin D plays also an important role in female reproduction, because vitamin D receptors are expressed in ovarian tissue, endometrium, fallopian epithelial cells as well as in decidua and placenta. We aimed to review the most updated evidence, which suggests a link between vitamin D metabolism and the development of some gynaecological diseases, such as endometriosis, uterine fibroids and polycystic ovary syndrome.