生殖医療技術の進歩 : 顕微授精の現状と問題点

Abstract

It has been over two decades since the birth of the first child conceived by in vitro fertilization (IVF). During the intervening years, technology has evolved; however, IVF has not solved the problems concerning sperm. The first successful pregnancies after the intracytoplasmic injection of a single spermatozoon into an oocyte (ICSI) were rapidly followed by the widespread use of this novel technique for the treatment of male factor infertility. Injection of motile (living) spermatozoa into the oocyte is the most important factor in obtaining good results and other sperm parameters, anti-sperm antibodies and sperm origin, i.e., ejaculated, epididymal and testicular, do not have a strong influence on the outcome of ICSI. ICSI has revolutionized the treatment of male infertility and the application of ICSI is rapidly expanding around the world. However, this technique avoids the natural process of sperm selection and fertilization. Therefore, it is of utmost importance to monitor carefully the development, throughout childhood and into adulthood, of individuals born as a result of ICSI in order to assess its safety. ICSI should only be used for specific indications until its safety has been established. In this paper, the current status of two new approaches, ICSI with spermatid and donor oocyte cytoplasm transfusion, is also reviewed.