Initially used exclusively for severe male factor infertility, ICSI has now acquired additional indications. Poor oocyte quality, thickened zona pellucidae, advanced age, limited number of oocytes due to poor response and moderate male factor infertility are some of these new indications for ICSI. Very recently, cyropreserved oocytes have been fertilized by ICSI and the resultant embryos have given rise to live birth IVF success rates. This procedure will undoubtedly be applied in more settings in the future and may even become the method of choice for fertilizing all oocytes so that there are no unexpected fertilization failures and to avoid polyspermic fertilization.
There has been no breakthrough in the field that has had a greater impact than Intracytoplasmic Sperm Injection, ICSI.
When first proposed by Dr. Van Steirteghem* in Belgium, the concept of directly injecting an entire sperm into an oocyte was thought to violate all that we thought we knew about the fertilization process. Even if successful, the procedure was felt to bypass the laws of natural selection and there was concern that a rash of abnormal babies would be the result. We know now that these were unwarranted concerns. ICSI has become a routine procedure in most fertility clinic laboratories.