ICSI – Intracytoplasmic injection of spermatozoa

ICSI, or an intracytoplasmic injection of spermatozoa, is an egg cell culture technique from a group of micromanipulative techniques where one spermatozoid is directly injected into the cytoplasm of the egg cell, thereby achieving its fertilization and creating an embryo.

This method was developed in 1991 and has revolutionized the treatment of more severe forms of male infertility, which back then had a very small chance of success using the classic IVF procedure.

Namely, using the ICSI procedure, it is sufficient to have a very small number of spermatozoa.

Certain IVF centers have standardized the ICSI procedure in all situations due to work standardization and less chances of failure of fertilization. However, this does not necessarily have to be the best solution since the choice of spermatozoa is largely based on the morphological evaluation by the embryologist. This avoids the natural selection of the best spermatozoa. Numerous techniques have been developed to improve the selection of the best spermatozoa (PICSI, MACS).

ICSI is used in cases where:

  • When there is a low sperm count and reduced mobility present
  • After all techniques of surgical extraction of spermatozoa (TESA, TESE).
  • In normal spermograms, after previous cycles indicating there was a low rate of fertilization of egg cells or even complete lack of fertilization.
  • It is advisable that in cases where we have a greater number of ovum cells, even in normal spermograms, one part is fertilized by the IVF method, and one part with the ICSI method in order to avoid the possibility of failure of fertilization.

Large studies on the topic of IVF or ICSI have shown that, if these indications are observed, the rate of success is not differentiated by one or the other method.



Embriotransfer is the ultimate stage in undergoing fertilization. After fertilization, embryos are stored in the incubator for 3-5 days, depending on the quality and number of eggs obtained after aspiration. If you reach the 5th day in the incubator (blastocyst stage), probability of conception increases by 50%. Specialized catheter is used for embryos transfer to the patient’s womb. Depending on the patients age and earlier cycles, usually the number of embryos transferred ranges 1-3, but in all cases gynaecologist and an embryologist are the ones who suggests the patient’s best solution.