Polycystic ovarian syndrome (PCOS) as on of the most common endocrine pathology in the reproductive age female around the world is a multifactorial disease with a genetic predisposition exposed to certain environmental factors lead to the expression of PCOS features. Most common environmental factors include obesity and insulin resistance. Some hypotheses also include fetal androgen exposure.
ICSI is a procedure in which a sperm is injected directly into an egg to achieve fertilization. It is offered to women with PCOS failing to ovulate with clomiphene citrate followed by chronic low-dose gonadotropin protocols.
Vitamin D was found to be involved in the regulation of several hormones in the body including the anti-Müllerian hormone (AMH), follicle-stimulating hormone, estradiol, and progesterone. In addition, a correlation between vitamin D deficiency and PCOS due to the effects of vitamin D receptors on LH and sex hormone-binding globulin levels, the incidence of insulin resistance, testosterone levels, and aromatase gene expression. (57)
It has been suggested that VD plays a role in the decidual function and embryo implantation. Therefore, in the last few years, due to emerging evidence of the role of VD in female human reproduction including implantation, there was an increasing interest in investigating the correlation between vitamin D deficiency and in vitro fertilization outcome (66).(58) Some investigators have found better IVF outcomes in cases of sufficient VD status, whereas other studies failed to show any correlation between serum or follicular fluid VD level and pregnancy outcome after IVF/ICSI