ICSI allows many men with male factor infertility to create genetically-related children. It is performed as part of an IVF cycle, where a single sperm is inserted directly into the egg to allow fertilization.
Most times, the sperm required for ICSI are retrieved through the ejaculate. However, for some men with no sperm in the ejaculate, there is still a possibility of fathering children. The sperm can be retrieved directly from the testicles [TESE] or from the epididymis [PESA].
Male factor infertility is present in up to half of all infertile couples, making it one of the most common causes of infertility. In the past, the only option for many male factor couples was intrauterine insemination (IUI) using donated sperm. Intracytoplasmic Sperm Injection (ICSI) is performed as a part of an IVF cycle wherein a single sperm is inserted directly into the egg causing fertilization. The ICSI procedure does not appear to damage the egg and optimizes fertilization rates in cases where a male factor exists. ICSI was a major advance in the treatment of male infertility, allowing virtually all men to father children, with the first case performed in 1990.
The decision to use ICSI is made in consultation with the couple, physician, and embryologists. At most fertility clinics this decision is made based on the sperm testing at the clinic. However, there are some instances where the semen sample collected at the time of retrieval is not optimal, and ICSI may be recommended at that time. ICSI is performed on the day of egg (oocyte) retrieval. A sperm sample is provided by the partner, and approximately 4-6 hours after the egg retrieval, individual sperm from this sample is injected into the mature eggs (fig 5). Fertilization rates with ICSI are typically about 80% of mature (competent) eggs. Of note, standard IVF insemination of eggs should yield the same fertilization rates, but is reserved for cases when the sperm is considered normal and there is no history of poor fertilization with IVF in the past.
Figure 5: Intracytoplasmic sperm injection (ICSI).
Many times the sperm needed for ICSI are retrieved from the ejaculate; however, men with no sperm can often still produce sperm for ICSI. The sperm can be retrieved directly from the testicles using testicular sperm extraction (TESE) or from the epididymis using percutaneous epididymal sperm aspiration (PESA). Fertilization rates using ICSI are typically high, and pregnancy success rates are higher compared to standard IVF culture when a sperm factor is the cause of infertility.
What is the success rate of ICSI?
Fertilization rates and pregnancy success rates using ICSI are typically comparable to those using standard IVF without ICSI. Years of follow-up on children conceived using ICSI have shown no increase in birth defects. There is some concern, however, that male offspring may have a slightly higher rate of infertility; however, this has not been demonstrated.