For Informational Purposes Only
What is ICSI?
ICSI is very similar to conventional IVF in that gametes (eggs and sperm) are collected from each partner. The difference between the two procedures is the method of achieving fertilisation.
In conventional IVF, the eggs and sperm are mixed together in a dish and the sperm fertilises the egg ‘naturally’. However to have a chance that this will occur, large numbers of actively swimming normal sperm are required. For many couples, the number of suitable sperm available may be very limited or there may be other factors preventing fertilisation, so conventional IVF is not an option. ICSI has provided a hope for these couples.
ICSI refers to the laboratory procedure where a single sperm is picked up with a fine glass needle and is injected directly into each egg (Figure **). This is carried out in the laboratory by experienced embryologists using specialist equipment. Very few sperm are required and the ability of the sperm to penetrate the egg is no longer important as this has been assisted by the ICSI technique. ICSI does not guarantee that fertilisation will occur as the normal cellular events of fertilisation still need to occur once the sperm has been placed in the egg.
Stages of IVF & ICSI Treatment
In general there are five stages to each cycle of IVF or ICSI treatment.
STAGE 1: Down regulation
Initially, the treatment starts by taking a nasal spray from day 21 of the cycle for 14 days to temporarily switch off the hormonal messages from the brain to the ovaries. After approximately 14 days on the nasal spray daily hormone injections are started for ovarian stimulation. The nasal spray continues to be taken in combination with the injections in order to prevent premature release of eggs (ovulation).
STAGE 2: Ovarian stimulation
Daily injections with hormones (gonadotrophins) should hopefully stimulate the ovaries to produce multiple eggs (follicles). The course of injections is usually for 11–13 days. Stimulation is monitored by ultrasound scans and there are usually at least 2 scans during the treatment. When the follicles reach a mature size a further hormone injection (hCG) is given to ripen the eggs and prepare them for collection approximately 36 hours later.
STAGE 3: Egg Collection
Egg collection is performed using a transvaginal ultrasound probe to which a needle is attached. The fluid within each follicle is gently sucked out into a test tube, via a special pump attached to the needle, and examined by an embryologist who checks for the presence of eggs under the microscope. Intravenous pain relief is given during the egg collection which usually takes around 15-20 minutes. Although some discomfort should be expected, the vast majority of patients tolerate the procedure without difficulty. Once the egg collection is finished, patients are taken to the recovery room and are usually discharged after a couple of hours.
On the morning of egg collection the husband/partner will be asked to provide a semen sample.
STAGE 4: Insemination
In IVF treatment the sperm and eggs are incubated overnight in a special fluid that provides them with all the right nutrients to allow fertilisation to occur. In ICSI treatment the eggs are injected with individual sperm. The following morning, the eggs are checked for signs of fertilisation. At this stage, depending on how many embryos have been formed some may be frozen and stored. The other embryos are allowed to continue to grow and develop for two or three days before transfer back into the womb (uterus). In some cases, the embryos may be allowed to develop further with the aim of reaching a more advanced stage (blastocyst) before transfer.
After the egg collection procedure patients are told when to contact the embryologist to be advised about the fertilisation and when to attend for embryo transfer.
STAGE 5 Embryo transfer
On the day of embryo transfer the embryologist will select the best embryo(s) to transfer. Embryos are usually transferred on the second, third or, occasionally, fifth day after egg collection. Usually one embryo is placed inside the womb (uterus). The procedure usually only takes a few minutes to perform and does not require pain relief. The doctor places the embryo into the uterus using a fine catheter, which is inserted through the cervix.
Following the embryo transfer patients are encouraged to resume normal activities. A hormone Gel (Crinone) is inserted into the vagina every evening for two weeks following embryo transfer. After this time, a pregnancy test is performed.
During treatment it may be necessary to alter the dose of the hormone injections depending on the response of the ovaries as monitored on scan.
Unfortunately not all patients respond to the drugs used for ovarian stimulation and sometimes it may be necessary to abandon the treatment cycle before egg collection.
Rarely, all of the eggs that have been collected may fail to fertilize. In these circumstances an appointment will be made with your consultant to discuss your treatment and future options.