الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The classic clinical definition of infertility is the absence of conception after 12 months of regular, unprotected inter-course. Vitamin D3, a secosteroid that is synthesized in skin and sequentially metabolized in liver and kidneys in humans, has been well-known for its function in maintaining calcium and phosphorus homeostasis and promoting bone mineralization. In recent years, there has been a growing interest in studying the association of vitamin D deficiency and infertility. It has been postulated that vitamin D receptors (VDR) are found in human tissues such as male and female reproductive organs and play a major role in facilitating the biological activity of Vitamin D. Vitamin D deficiency has been advocated as a possible cause of infertility in many studies conducted in the past several years. In the US, it has been estimated that about one third of the population is deficient in Vitamin D and infertility affects nearly 15.5% of the US couples and nearly 53 million people all across the globe. Polycystic ovary syndrome (PCOS) is a common cause of ovarian dysfunction in women with anovulation. The main symptoms are characterized by chronic anovulation, hyperandrogenism, and/or the presence of polycystic ovary morphology from ultrasound examination (5). Clinical manifestation of this disorder is associated with various degrees of gonadotropic and metabolic abnormalities determined by the interaction of multiple genetic and environmental factors. Low 25(OH)Vit D levels may exacerbate the symptoms of PCOS, including insulin resistance, ovulatory, menstrual irregularities, infertility, hyperandrogenism, obesity and elevate the risk of cardiovascular diseases.Many observational studies suggest a possible role of vitamin D in an inverse association between vitamin D status and metabolic disturbances in PCOS, but it is still hard to draw a definite conclusion in the causal relationship due to inconsistent findings from various individual studies and from a recent meta-analysis report of a systematic review. The