Pronounced “ick-see,” ICSI stands for Intracytoplasmic Sperm Injection. During regular IVF, many sperm are placed together with an egg in hopes that one of the sperm will enter and fertilize the egg on its own. With ICSI-IVF, the embryologist takes a single sperm and injects it directly into an egg. Fertilization failure, where no oocyte is fertilized, occurs in 3.52–20% of conventional IVF cycles, and even in 1–3% of ICSI cycles. So ICSI is used when the semen analysis is questionable or there is a history of poor or failed fertilization in the past. ICSI is also used when there are few oocytes available. One of the fears with conventional IVF is that more than one sperm can fertilize the oocyte and ICSI can prevent this from occurring. Our embryologist was one of the first few to perform ICSI in the United States.
Dr. Huang says, “as with regular IVF, you’ll take ovarian stimulating drugs, and we will monitor your progress with blood tests and ultrasounds. Once your follicles have reached the appropriate size, you’ll have the egg retrieval, where eggs are removed from your ovaries with a specialized, ultrasound-guided needle. Your partner will provide his sperm sample that same day, unless you’re using a sperm donor or previously frozen sperm.”
Once the eggs are retrieved, an embryologist will place the eggs in a special culture, and using a special microscope with a tiny needle, a single sperm will be injected into an egg. This will be done for each egg retrieved.
If fertilization takes place, the embryos will be cultured in a special incubator for several days. If the embryos appear healthy, they will be frozen and an embryo or two will be transferred to your uterus via a catheter placed through the cervix. This is currently done in the next cycle.
Risks of ICSI
ICSI-IVF comes with all the risks of a regular IVF cycle, but the ICSI procedure may introduce additional ones.
A normal pregnancy comes with a 2–4% risk of major birth defects. ICSI treatment carries a slightly increased risk of birth defects, but it’s still rare.
Some birth defects are more likely to occur with ICSI-IVF, specifically Beckwith-Wiedemann syndrome, Angelman syndrome, hypospadias, and sex chromosome abnormalities. They occur in less than 1% of babies conceived using ICSI with IVF. Many feel that this increase is the result of using poor quality sperm rather than the ICSI procedure itself.
There is also a slightly increased risk of a male baby having fertility problems in the future. This is because male infertility may be passed on genetically.
These additional risks are why many doctors are saying ICSI should not be used for every IVF cycle. If you need ICSI to conceive, you should discuss the pros and cons of using this assisted reproduction technology with your doctor.
The ICSI procedure fertilizes 50–80% of eggs. Fertilization isn’t guaranteed even when a sperm is injected into the egg. Remember that fertilization rates don’t tell you the clinical pregnancy or live birth rates. Once fertilization happens, the success rate for a couple using ICSI with IVF is the same as a couple using regular IVF treatment. Although, some studies suggest that implantation rates, the number of embryos that implant per transfer, might be higher in ICSI embryos compared to conventional IVF.