الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Generally, infertility has been usually considered as one of the vital, severe and expensive health issues in diverse societies. Causes of infertility cannot be present in about 25% of the infertile couples. who are examined for fertility, where unknown causes of infertility is described with normal semen parameters together with a normal uterine cavity , maximal ovulatory functions, presence of patent tubes and failure of achieving pregnancy after at least 1year of unprotected intercourse.
Assisted reproductive technique (ART), especially ICSI can be of beneficial effect in cases of unknown etiology of infertility to fertilize all oocytes. The routine use of ICSI in couples with unexplained infertility offers significant benefit. Various studies dealing with the etiology of infertility from different aspects, one of these factors the high concentration of leptin hormone in the serum which considered as one of main factors for associated with infertility in many researches.
It is well known the leptin hormone is related to adipokine family and synthesized by white adipose tissue. The mode of action of leptin may be include the regulation of food intake and energy homeostasis through it is effect on the central nervous system .The detection of obesity gene (leptin or ob gene) was cloned and sequenced for the first time in 1994. This gene is subjected for mutations which creates a new gene responsible for diabetes and sever obesity in animals and human beings.
Many organs in the body specially the brain containing leptin receptors. In several studies, they found that the level of leptin in the serum is liked with body fat mass extent and allocation, and play a role in supplying the CNS with peripheral stimulation on the sufficiency of nutritional condition for adequate reproductive task.
In addition to the role of leptin hormone in inducing obesity, leptin is concerned with regulating of several physiological tasks, like metabolism, growth and reproduction. Where, leptin hormone is responsible for regulation and stimulation of hypothalamic-pituitary-gonadal axis, via its direct effect on the hypothalamus in the brain and regulate the release of GnRH from the hypothalamus.
Assisted reproduction is a complicated process involving multiple stages of ovarian stimulation, ovum pick up, fertilization, embryo cleavage and implantation. The ultimate goal of all these procedures is achievement of a viable intra uterine pregnancy as a step of achievement of a healthy baby. Good quality of all reproductive components and primarily embryos has a positive impact on success rates. Definitely, better selection of embryos is one of the greatest challenges in in vitro fertilization.