Intracytoplasmic Sperm Injection, ICSI
The introduction of ICSI revolutionized the treatment of male infertility allowing men with as few as one sperm to father genetically related children. Prior to ICSI, the only option for couples with moderate to severe male infertility was to use a sperm donor, donor embryos or adoption.
ICSI is conducted in conjunction with an IVF cycle. Once the follicles mature, the eggs are retrieved transvaginally using ultrasound guidance. Once retrieved they are transferred to the embryology laboratory where the eggs are separated from the follicular fluid.
ICSI is a delicate microsurgical procedure that involves injecting a sperm directly into an egg. As long as one viable sperm can be obtained, ICSI can cause successful fertilization. The sperm may be extracted from the ejaculate or directly from the testicles using testicular or epididymal (collection system near the testicle) sperm extraction (TESE). The sperm insertion usually does not damage the egg. If viable sperm are available, the IVF success rates are usually unaffected by the semen characteristics and sperm quality. ICSI is also used in cases where a man who previously had a vasectomy wishes to start a new family. There are treatment options for these men.
Our embryologists have extensive experience performing the delicate ICSI procedure and fertilization rates greater than 50% are usually achieved. The egg must be gently held in place by a micro manipulator while the sperm is carefully injected. Once ICSI is complete, the embryo is placed into the incubator until ready for transfer.
Some studies have indicated an increase in the risk of sex chromosome abnormalities in ICSI pregnancies. The incidence of congenital birth defects may also be higher with ICSI, but it is unclear if this is due to the procedure itself, or to inherent problems with the sperm. It is well known that men with sub optimal semen parameters have a higher frequency of chromosomal abnormalities such as Klinefelters syndrome. Microdeletions of the AZF region of the Y chromosome have been found in up to 15% of men with low sperm counts. These microdeletions can be passed on to any male embryos that result. Men with low semen parameters are also more likely to have one of several cystic fibrosis gene mutations.
We recommend that men with low sperm counts be tested for the above-mentioned abnormalities (such as karyotype or chromosome analysis, Y micro deletion assay, and Cystic Fibrosis mutation screening). If abnormalities are detected, genetic counseling is recommended. Genetic testing prior to embryo transfer (preimplantation genetic diagnosis, PGD), chorionic villi sampling or amniocentesis may be appropriate in selected cases.
The potential advantages of selecting ICSI include: (1) enhancement of the fertilization rate thereby increasing the number of fertilized eggs available for transfer into the uterus or for freezing, (2) fertilization of eggs when the chance for successful fertilization under normal insemination protocols is anticipated to be low and (3) minimizing the likelihood of not getting any eggs to fertilize when the semen parameters are marginally abnormal. It is also possible that none of the eggs will fertilize, even with ICSI.
The potential disadvantages of ICSI include: (1) potential for unknown risks to the egg or embryo, (2) the process of ICSI itself may damage embryos or it may degenerate the egg immediately.