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Intracytoplasmic Sperm Injection (ICSI)



ICSI (Intracytoplasmic Sperm Injection) is comparably new but already a well developed laboratory procedure which was first applied in 1992. ICSI was developed to overcome the male factor of infertility. In case of ICSI a single spermatozoon is injected into the cytoplasm of each oocyte with a thin glass needle. The first child as a result of ICSI procedure was born in 1992. ICSI became a replacement for two previously applied laporatory methods – PZD (Partial Zone Dissertion) and SUZI (spermatozoon under-pellucid zone injection) as it allows to achieve higher percent of fertilization.


In this section you’ll find full information on the ICSI procedure:

  • Who is recommended ICSI?
  • Description of the ICSI procedure
  • Efficiency of ICSI
  • Risks of ICSI


Who is recommended ICSI?


  • Married couples whose oocytes haven’t been fertilized during the standard IVF cycle or whose percent of artificial insemination is very low,
  • Men with pathological sperm abnormalities (e.g. low quantity of spermatozoa, spermatozoa poor mobility, high percent of spermatozoa with pathological morphology, high level of anti-sperm anti-bodies in the sperm), which reduce the probability of successful treatment with standard in vitro fertilization (IVF),
  • Men with azoospermia (full lack of spermatozoa in the ejaculate) whose spermatozoa are generated through the biopsy of the testicle. The reason for such pathology is the lack or impassability of seminiferous tracts, as well as unobstructive azoospermia,
  • In case of using cryopreserved sperm with low quantity of spermatozoa or of poor quality,
  • Married couples who are expected to have low percent of fertilization during standard IVF, e.g. patients with the severe type of endometriosis or infertility of unknown genesis.


Description of ICSI procedure


The first phases of ICSI have the same process as the standard IVF cycle. The woman is prescribed injections of hormonal medicines which stimulate the maturing of several follicles in ovaries. Oocytes are extracted during an ambulatory procedure under the ultrasound control and are placed in a special medium for cultivation. After the oocyte generation they are examined under the microscope and their quality is assessed. Afterwards they are placed in the incubator for 2-6 hours and then the cumulusous cells surrounding the oocyte are removed to assess the level of oocyte ripeness, as ICSI can be conducted only with mature oocytes. Immature oocytes can remain in the medium for the cultivation and ICSI can be conducted on the next day, if oocytes finally become mature.


Spermatozoa generated from the ejaculate or through the biopsy of the testicle or the epididymis (TEZA/TEZE/PESA) are processed in special mediums. Spermatozoa can be generated from the frozen sperm sample.


After the assessment of the oocyte maturity spermatozoa are placed in the special medium, spermatozoa with normal morphology are selected, immobilized and absorbed through the thin glass needle and then are injected immediately into the oocyte. The oocyte is immobilized with a holding pipette. This is a very delicate procedure and a micromanipulator is required for this procedure. Such sequence of activities is repeated for each generated oocyte. The oocyte membrane is very elastic and the microscopic opening by the micro-needle is skinned over very quickly, but, however, 1% of oocytes may be damaged during the ICSI procedure.


On the next morning oocytes are examined to check the fertilization. The developed embryos are cultivated during next 2-5 days when their partition and further development takes place. Not all fertilized embryos start partitioning and some of them may even stop developing on the early stages. Usually 2 embryos are transferred to the uterine cavity (3 embryos in exceptional cases). The rest of embryos of good quality are cryopreserved for the future transfers to the uterus.


Medicinal therapy to support the lutein phase is prescribed according to the same regimen, as after the standard IVF cycle. 


ICSI efficiency


As of today ICSI is applied for more than 15 years and several hundred thousand children have been born through ICSI. The percent of fertilized oocytes through ICSI makes up 70% and about 80% of fertilized oocytes start normal partition. The risk that no oocyte will be fertilized as a result of ICSI makes up less than 5%. The efficiency of ICSI is comparable with the efficiency of traditional IVF. Other factors influencing on the frequency of pregnancy with ICSI include the age of women, the duration of infertility and the quantity of transferred embryos.


ICSI risks


Besides the well known risk connected to the standard procedure of in vitro fertilization, specialists have expressed assumptions on possible additional risks connected to the ICSI procedure. Mainly these apprehensions conditioned with the injection of a defective spermatozoon into the oocyte, as ICSI skips the phase of natural selection of spermatozoa for fertilization which may cause the birth of sick children. Besides that concerns have been expressed that as a result of ICSI a defective oocyte may be fertilized (in case of a natural conception and during the standard IVF cycle the natural selection process takes place and the probability of fertilization of a defective oocyte is low.


However the results of examination of children’s health born with ICSI have been generally encouraging although there is no sufficient quantity of information on long-term impacts of this procedure.


There is information on high probability of genetic pathologies among children born through ISCI method, in particular Sherenevski-Turner syndrome and Klyaiferter’s syndrome. However there is no reason to assume that this is connected to the ICSI procedure. As ICSI is conducted in cases of severe male infertility genetic pathologies that have probably caused problems with father’s spermatogenesis and may be transmitted to his son.


This is confirmed by researches which have detected connection between male infertility and following pathologies:


  • Y chromosome defects called “microdeletions”;
  • abnormalities in chromosome quantity and structure, e.g. Klyainfelter’s syndrome and translocations;
  • mucoviscidiosis;
  • defects of the androgen receptor’s gen.


Before starting the treatment with ICSI method, couples should pass medical-genetic consultancy and examination to check the availability of above mentioned pathologies. In case of detection of a genetic pathology it’s necessary to consult with the geneticist and get full information on the risk of transfer of the given pathology to posterity. 



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