What is ICSI?
In ICSI, a single sperm is selected and inserted into an egg that has been obtained through IVF treatment. Although ICSI has been routinely used for almost 20 years, it is still considered a major development for the treatment of male infertility. It has been the solution for cases of very low-count, poor-quality and / or difficult-to-retrieve sperm.
With the use of fine micro manipulator equipment under microscopy, a sperm can be manually injected into an egg, triggering its fertilization. ICSI is feasible because a sperm is 100 times smaller than an egg.
After fertilization has occurred, 2-3 days or 5 days later (blastocyst stage), the best quality embryo(s) are selected and transferred back in the womb, as in IVF without ICSI. The number of embryos transferred entirely depends on your individual circumstances (for instance age, number and quality of available embryos, previous failed attempts).
The end goal of an IVF with ICSI is to have an ongoing, healthy pregnancy followed by a live birth.
Who can benefit from ICSI?
ICSI is the method of choice for male infertility, when the availability, quality and / or quantity of sperm are very limited. As a matter of fact, ICSI was used at the beginning, when the technique was described, to solve male infertility cases.
Men with a very low-count (small number of sperm in the semen), defected-motility (limited movement) and / or abnormal-morphology (misshaped) sperm are good candidates for ICSI. In these cases, the good quality sperms from their samples, which exist but in a low percentage, are extracted and used for the injection.
This method is also recommended to couples that have a history of previous unsuccessful attempts with IVF.
ICSI may also be the method of choice, if the sperm comes from a frozen sample and its quality / survival after thawing is not as optimum for usage with conventional IVF.
ICSI can also benefit men that have undergone a vasectomy or have azoospermia (absence of sperm in the semen). In these cases, sperms are collected surgically form where they are produced and stored in the testes or the epididymis (a tube structure inside the scrotum where sperms are generated and matured).
How is ICSI done?
ICSI is practically a variation of the conventional IVF cycle, and it follows exactly the same steps up until egg collection.
The sperms for ICSI can be sourced on the day of egg collection through:
- Fresh sperm collection
- Thawing of a frozen sample
- Minor surgery, for instance with TEsticular Sperm Extraction (TESE) or Percutaneous Epididymal Sperm Extraction (PESE)
- Microsurgery, for instance with TEsticular Sperm Aspiration (TESA) or Percutaneous Epididymal Testicular Aspiration (PESA)
If the procedure of retrieving sperm is estimated to be difficult or time-consuming for it to happen on the same day as egg collection, then it will be carried out before the IVF cycle begins, and the samples will be frozen until needed. Alternatively, the procedure can be performed 24 hours prior ICSI, with the sperms being incubated in the laboratory until needed the next day.
The embryologist, who will assess the sperms before ICSI, examines their morphology (shape) and ability to move (motility) under a microscope. The best sperms are selected and placed in a dish, until the mature eggs become also available.
Our embryologist, next, uses a sharp and hollow needle to pick up a single sperm. In the same time, a mature egg is held in place with a micropipette, through the use of a micromanipulation device. The sharp needle is then used to pierce the immobilized egg, and the single sperm is released into its core. The needle is carefully retracted and the injected egg is placed in a dish and back in the incubator. This procedure is repeated for all available eggs.
The rest of the steps: fertilization, embryo transfer, first pregnancy test and ultrasound scan are performed exactly the same as in IVF. Preimplantation Genetic Diagnosis (PGD) and / or Preimplanation Genetic Screening (PGS) testing for any chromosomal abnormalities can be performed before embryo transfer.
How successful can ICSI be?
Currently ICSI is used to fertilize eggs as a routine technique in more than 90% of couples undergoing IVF. These cases, apart from male factor infertility, include unexplained infertility, advanced maternal age, or a previous failed attempt with conventional IVF, among other reasons.
About 70-85% of the eggs injected with sperm in ICSI become fertilized. However, the overall outcome of ICSI depends on your individual circumstances. Chromosomal integrity of the sperm used and maternal age are the two main factors responsible for a negative outcome. Normally, younger women exhibit a high percentage of success with ICSI, but that declines dramatically with women over 45.
If you have further questions about ICSI, our specialist doctors can provide you with more information and consult you on all available options, depending on your individual circumstances.