Intracytoplasmic sperm injection is a laboratory procedure developed to help infertile couples undergoing in vitro fertilization (IVF) due to male infertility or subfertility. ICSI is a form of micromanipulation that involves the injection of a single sperm directly into the cytoplasm of a mature egg (oocyte) using a glass needle (pipette). This process increases the likelihood of fertilization when there are abnormalities in the number, quality, or function of the sperm.
ICSI treatments are generally not successful when used to treat infertility that are due to poor egg quality.
A variety of abnormalities can cause male infertility or subfertility. Sperm can be absent from the semen (azoospermia). Sperm may have poor motility (asthenozoospermia) or have an increased percentage of abnormal shapes (teratospermia). There may also exist functional abnormalities which prevent the sperm from binding to an egg and fertilizing it. Indications for Intracytoplasmic Sperm Injection:
Very low numbers of motile sperm
Problems with sperm binding to and penetrating the egg
Presence of antisperm antibodies thought to be the cause of infertility
Prior failure with standard" In Vitro Fertilization (IVF)
Use of frozen sperm limited in number and quality
Obstruction of the male reproductive tract not amenable to repair. Sperm may then be obtained from the epididymis by a procedure called microsurgical epididymal sperm aspiration (MESA) or from the testes by testicular sperm aspiration (TESA)
Fertilization occurs in 50% to 80% of injected eggs. The ICSI process may damage a small percentage of eggs. The fertilized egg may fail to divide, or the embryo may arrest at an early stage of development.
Approximately 30% of all ICSI cycles resulted in a live birth, which is comparable to rates seen with standard IVF. Younger patients may achieve even more favorable results. Factors such as poor egg quality and advanced maternal age may result in lower rates of success.
ICSI does not increase the incidence of multiple pregnancies as compared to standard IVF. Since ICSI is a relatively new technique, first performed in 1992, long term data concerning future health and fertility of children conceived with ICSI is not available.
Studies have shown that the incidence of a congenital malformation called hypostapdia (urethra opening on underside of penis) is higher in babies conceived through ICSI. This is an area of ongoing investigation.
Due to the fact that some causes of male infertility are related to genetic problems, male babies may have fertility issues in adulthood.
In spite of these concerns, ICSI is a major advance in the treatment of severe male infertility.