Intracytoplasmic sperm injection. Why and when ICSI is used?
Infertility has various causes. It may be female or the male factor, but most of the times it’s more complicated and both parties are at play. What can be helpful in such cases? Is ICSI a solution or is this procedure more effective for couples with male factor involved?
Watch 3on1 #IVFANSWERS to get more information about Intracytoplasmic sperm injection. 3 fertility experts answer 1 question about ICSI:
- Dr Carolina Alonso Muriel – Embryologist & Egg Donation Program Coordinator at URE Gutenberg Centre Reproduction Unit
- Dr Oksana Babula – Reproductologist from EGV Clinic
- Dr Katharina Spies – ObGyn Assisted Reproduction Specialist at ProcreaTec
Answer from Dr Muriel
In Vitro Fertilisation (IVF) is the most common type of assisted reproductive technology (ART). It’s a laboratory procedure which involves retrieving eggs from a woman’s ovaries and fertilizing them with sperm in order to produce embryos. Once fertilized, a limited amount of embryos are transferred into the recipient’s uterus, so that they can continue developing naturally inside.
The insemination of the oocytes can be carried out with conventional fertilisation methods, or by using Intracytoplasmic Sperm Injection (ICSI). Conventional IVF consists of culturing the eggs with a certain amount of sperm – around 100,000 sp/ml. Conversely, ICSI only uses a single, pre-selected sperm, which is directly injected into the cytoplasm of a mature egg.
Conventional IVF fertilisation was traditionally the method of choice when treating couples suffering from non-male factor infertility. However, the use of ICSI has increased dramatically in all treatment scenarios, as it helps avoid total fertilisation failure due to unknown causes. Today, we use ICSI exclusively in all of our cases.
Answer from Dr Babula
Infertility can be caused by the female or the male factor; most of the time, we see cases where both sides are at play. Male factor infertility can be caused by, for example, issues with sperm, such as low motility or DNA fragmentation; female factor infertility can be caused by many more reasons, such as low egg quality due to aging, congenital issues, or others.
In both cases, IVF and ICSI can help. What, however, is the difference between them? During IVF we allow the sperm to naturally fertilize the egg, while during the ICSI procedure an embryologist selects a single sperm and directly injects it into the oocyte. The latter option is especially recommended for women of advanced age, even if the sperm quality is perfect. This is because during ICSI, embryologists perform certain tests to make sure the best possible sperm is selected. ICSI is then a fertilisation method which allows patients of all types to generate a good quality embryo.
Answer from Dr Spies
The day of the egg retrieval, the mature eggs that we obtain can be fertilised using conventional IVF or the ICSI technique. Conventional IVF is simply combining sperm with eggs in a laboratory. The ICSI method involves the embryologist selecting a single sperm with a fine glass needle and injecting it directly into the egg. Differences in the fertilisation rates depend on the quality of eggs and sperm – right now, embryologists largely prefer the ICSI route. In certain circumstances, ICSI should be the only method employed. These circumstances consist mainly of sperm defects, like oligo, asteno, teratozoospermia or a combination of all of them. In these cases, ICSI should always be performed, as altered sperm quality has a major impact on the fertilisation process. In severe cases, an additional technique for sperm selection, such as Fertile Chip, may be used before proceeding to ICSI.
Another indication for ICSI is when the sperm is obtained by testicular aspiration or biopsy, or in the case where frozen sperm is to be used. When using high valued sperm, we don’t want to take the risk of a possible fertilization failure. But what if the sperm quality is good? If there is a normal ovarian reserve, if no former treatments have been performed that indicate a future fertilisation problem, or if the couple wishes to only use conventional IVF, we can accommodate that wish. The advantage of conventional IVF is that it’s easier and cheaper to perform and fertilisation takes place in a slightly more “natural” way.
In patients who have a limited ovarian reserve or highly valued eggs (for instance, in egg donation treatments), we always recommend ICSI. If the patients decide to do preimplantation genetic diagnosis of their embryos, now called PGT-A, we would also recommend ICSI. The same is true for frozen egg cycles. Lastly, we always recommend ICSI over conventional IVF if we suspect previous fertilisation failures.
In summary, the clearest indication for ICSI is a diagnosed male factor. Other scenarios in which it would be the recommended course of action are situations when a risk of fertilisation failure is present or if we want to guarantee the highest fertilisation rates. In clinical practice, almost all couples use ICSI; very few patients use conventional IVF, or a combination of conventional IVF and ICSI.