Infertility Treatments: Intracytoplasmic Sperm Injection (ICSI)
ICSI is a technique sometimes used with in vitro fertilisation (IVF) in which one sperm is injected directly into one egg in order to fertilise it. This is especially useful for men with very low sperm counts since ICSI ensures that the sperm reaches the egg directly rather than waiting for the sperm to naturally fertilise the egg. Thus, ICSI is sometimes used as a treatment method for male infertility.
What Can ICSI Help Treat?
There are a variety of underlying fertility conditions that ICSI may help treat. The specific male fertility problems that ICSI is used to treat are:
- low sperm count
- low sperm motility
- total absence of sperm in the semen
- damaged or absent vas deferens
- retrograde ejaculation
- irreversible vasectomy
- immunological factors (such as a very high white blood cell count in the semen)
- other conditions that prevent the fertilisation of the egg
Men who have been diagnosed with testicular cancer may also want to consider freezing a semen sample prior to treatment since this sample can later be used in ICSI.
How ICSI Works
Since ICSI is always used with in vitro fertilisation, the process starts with preparation for this procedure. The woman is given fertility drugs to stimulate egg follicle development and ovulation. Her mature ova are then retrieved to use during ICSI.
In additional preparation for ICSI, sperm is collected from the man. In cases where it is possible, sperm can be collected from a semen sample. This is the preferred method since it is less invasive, but for some men this may not be possible. An alternate option is to harvest the sperm directly from the man's testicles using a testicular biopsy under anesthetic.
The single sperm is then injected directly into the woman's harvested egg with a very delicate needle. The egg will reseal itself after the needle is withdrawn, just as it does in the process of natural fertilisation when the sperm breaks through its outer membrane.
As in in vitro fertilisation without ICSI, the fertilised egg is then allowed to develop for a few days before being transferred back into the woman's uterus in the form of an embryo.
Effectiveness of ICSI
ICSI is currently the most successful treatment for male infertility, with fertilisation rates of 60%-70% depending on quality of the sperm used. However, once the egg is fertilised, the success rates of ICSI in conjunction with IVF remain the same as conventional IVF – a 20%-25% chance of live birth. This is because overall effectiveness still depends on the fertilised egg developing properly in addition to successful implantation into the uterus. In some cases, assisted hatching may be used to increase the chances of implantation.
One concern about ICSI is the possible health impact of this procedure on any resulting children. ICSI is often used with men who have poor sperm quality, and the method entails using any sperm to fertilise the egg as opposed to the strongest one (which is what happens in nature). Because it is possible that a weaker, poorer quality sperm might be used in ICSI, congenital defects may be passed on at a higher rate than naturally or with other methods of IVF.
Also, because ICSI is a relatively new procedure, the long-term effects for resulting children have yet to be properly analyzed. So far, no studies have shown any increased chance of physical, developmental, or congenital problems in children conceived using ICSI.
Couples who want to conceive using ICSI are still advised to analyze their family history for genetic diseases and disorders and consult with a doctor. They may also want to consider pre-implantation genetic diagnosis (PGD).
Finally, because ICSI is used in conjunction with IVF, the risks of IVF apply here too; namely, increased chances of ectopic pregnancy and multiple births.
However, ICSI is still a viable choice if done by a reputable clinic. For some facing the only other alternatives of adoption, sperm donors, or never having children, the risks if ICSI pale in comparison to the possible benefits.