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Injection of a sperm cell into the oocyte

Intracytoplasmic sperm injection is an additional method to IVF treatment. In this procedure, a sperm cell is injected directly into the female oocyte. This sperm cell is obtained from the ejaculate – or surgically from the testicle or epididymis. This means that there is no independent fertilisation of oocyte and sperm.
The ICSI method is helpful when sperm motility or quantity is severely limited or fertilisation has failed with conventional IVF treatment. The steps up to oocyte retrieval (link to IVF/treatment steps) are identical for IVF and ICSI.

Video: Microinjection in the Laboratory

The oocytes are fixed under a special microscope with a holding pipette. A sperm is then lifted into a thin injection pipette and injected into the oocyte. ICSI (microinjection) mimics the natural process of a sperm penetrating the oocyte. Using this worldwide established method about 50 to 70% of the retrieved oocytes can be fertilised. 

ICSI Procedure

The ICSI procedure is almost identical to that of in vitro fertilisation (IVF). The key difference lies in step 6 – the fertilisation of the eggs: While in IVF the sperm fertilises the egg naturally in the laboratory, in ICSI a single sperm is injected directly into the egg using a fine pipette. All other treatment steps are essentially the same.

Retrieval and fertilisation of multiple oocytes
Through controlled hormonal hyperstimulation, we increase the chances of retrieving multiple oocytes to successfully fertilise them and transfer one to three embryos into the uterus. Hormonal stimulation with genetically engineered FSH or HMG has proven successful. To prevent premature ovulation, FSH or HMG stimulation is combined with a GnRH agonist or antagonist.

By ultrasound and blood test
During the stimulation treatment we check the growing follicles by ultrasound. In parallel, we measure the hormone estradiol (E2) in the blood, possibly also LH and progesterone. In this way, we determine the most favourable time for obtaining mature oocytes capable of fertilisation.

Timely oocyte retrieval 
When the most appropriate time for oocyte retrieval has arrived, we induce ovulation by injecting hCG so that the oocytes can be retrieved from the follicle after about 36 hours. 40 hours later ovulation would occur, so the oocytes would be lost.   

Outpatient procedure under anaesthesia 
The puncture of the follicle for oocyte collection is performed from the vagina using ultrasound. A general anaesthetic is not absolutely necessary, but makes the procedure much more comfortable. In addition, sufficient oocytes can then be obtained even under difficult puncture conditions. If there are no complications, you can go home the same day.
 

Fast and germ-free to the laboratory
On the day of egg retrieval, a semen sample is also collected. This can be provided either at home or at our clinic. If the sample is collected at home, it must be brought to our laboratory immediately. In the laboratory, the semen sample is washed and prepared for ICSI treatment using specialised sperm preparation techniques. ICSI is used in cases of impaired sperm parameters, such as reduced sperm concentration, motility or abnormal morphology.
Cryopreserved sperm or cryopreserved testicular sperm can also be used for ICSI treatment.

The eggs are held in place using a holding pipette under a specialised microscope. A single sperm is then drawn into a fine injection pipette and injected directly into the cytoplasm of the egg. In this way, ICSI mimics the natural process of a sperm entering an egg. Each mature egg is treated individually. The following day, we examine the eggs in the laboratory to determine which have been successfully fertilised, as indicated by the presence of two pronuclei. With this internationally established technique, approximately 50 to 70 per cent of the retrieved eggs can be successfully fertilised. Today, ICSI treatment makes it possible to achieve pregnancy even when only a very small number of sperm are available.

For the transfer back into the uterus, we aspirate a selected blastocyst using a thin catheter and insert it into the uterus. The transfer is monitored via ultrasound from the abdominal wall and is a painless procedure. To achieve good pregnancy chances, the transfer of a blastocyst is performed on day 5 of embryonic development. In order to make the most accurate predictions possible, we use artificial intelligence (AI) to assess embryonic development in the embryoscope. This allows us to make more precise predictions about the live birth rate and the risk of early miscarriage due to developmental disorders. Even after transferring just one blastocyst, very good pregnancy rates can now be achieved, especially in young couples, while avoiding multiple pregnancies.

ICSI or IVF – which method is right for you?

Whether ICSI is a suitable option for you depends on your individual test results and any previous fertility treatments. A key factor is the assessment of male fertility. ICSI may be recommended in cases of:
 

  • Impaired sperm quality: low sperm count, reduced motility or abnormal sperm morphology, collectively known as OAT syndrome (oligoasthenoteratozoospermia)
  • Absence of sperm in the ejaculate (azoospermia), when sperm are surgically retrieved from the testicles (TESE) or epididymis (MESA)
  • Failed fertilisation or very low fertilisation rates in a previous IVF cycle
  • Use of cryopreserved eggs or thawed sperm samples
  • Planned preimplantation genetic testing (PGT)
  • Increased sperm DNA fragmentation


We carry out all the necessary diagnostic tests, from semen analysis and sperm DNA fragmentation testing to CatSper analysis, in our andrology department. At the MVZ PAN Institute, our specialised reproductive medicine facilities and fertility laboratory are conveniently located on the same premises. The close proximity of the treatment area and fertility laboratory ensures well-coordinated and safe procedures.
 

  • Dedicated cleanroom laboratory on site
  • Certified quality management system
  • Transparent pregnancy and live birth rates
  • Close integration of fertility treatment and laboratory services

What are the chances of success and risks of ICSI?

As with IVF, the chances of success with ICSI depend on individual circumstances, particularly the woman's age and the quality of the eggs and sperm. The potential risks associated with hormonal treatment and egg retrieval are also largely the same for both procedures. Differences may arise in particular from the underlying fertility problems and the method of fertilisation. You can find detailed information about success rates and potential risks on our in vitro fertilisation (IVF) page. You can find our current pregnancy rates here.


Which medications are used during ICSI?

The hormonal preparation for ICSI is generally the same as for IVF. Medications support egg maturation, allow ovulation to be carefully controlled and can help support embryo implantation. The medications used depend on your individual circumstances. For more information about the medications and how they work, please see Medication during IVF.


What additional procedures are available for ICSI?

Depending on your individual circumstances, additional procedures may be used alongside ICSI treatment. These include surgical sperm retrieval (TESE), specialised sperm preparation techniques such as ZyMot, and assisted egg activation using calcium ionophore. Other procedures, such as blastocyst transfer, single embryo transfer (SET) and embryo monitoring using an embryoscope and artificial intelligence (AI), can be used in both IVF and ICSI. Find out more about additional procedures.

A thin glass or plastic pipette is gently releasing a liquid droplet into a clear petri dish. The dish is placed on a shiny surface, suggesting a laboratory setting focused on scientific experimentation or analysis.