الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 96 |  |  |
| | | from | 96 | | |
Abstract
Assisted reproductive technology (ART) is a general term referring to methods used to achieve pregnancy by artificial or partially artificial means. The ultimate goal of assisted reproductive technique is to achieve successful implantation of a single high quality embryo. The concept of embryo quality is difficult to define but we cannot assert that embryo quality is optimal unless two criteria are met: (1) a chronologically and morphologically regular cleavage and (2) viable offspring develop after embryo transfer. There are many factors affecting embryo quality such as: Oocyte quality , Sperm quality, Method of ovarian stimulation, Vascular endothelial growth factor, nitric oxide(NO) and leptin , Culture system and Decidualizing Endometrial Stromal Cells, There are many embryo grading systems that differ in how they assign grades and in whether a low number grade indicates the best or the worst embryo. There are many ways to improve embryo quality and they are divided into two phases: 1. Pre fertilization phase including ovulation induction methods, oocyte quality improving, and sperm quality improving and pre fertilization medication.2. Post fertilization phase including the culture media, stage and number of embryo transferred, embryo gene therapy, method of transfer and others.