Fertilization failure after IVF or ICSI

IVF Laboratory / In Vitro Fertilization - IVF / Fertilization failure after IVF or ICSI

In many situations fertilization problems occur both in the conventional in vitro fertilization as well as in cases in which ICSI is used. Despite the preliminary tests and the recommendations, the fertilization failure or poor results fertilization can occur regardless of the efforts sustained.

The fertilization failure or poor results fertilization can occur due to several factors like the sperm quality, oocytes quality or a combination of these two.

Conventional in vitro fertilization failure

The fertilization failure or poor results fertilization can occur due to some problems that appear in any of the fertilization process steps.

- The impossibility of the spermatozoon to pass through the cell mass that surrounds the oocyte (cumulus).

- The impossibility of the spermatozoon to penetrate the zona pellucida (ZP) which surrounds the oocyte. In this case the problem can be assigned both to the spermatozoon and the oocyte: the spermatozoon can?t pass through a normal ZP or the oocyte is surrounded by an abnormal ZP.

The membranes of the spermatozoon and oocyte do not properly interact and so the spermatozoon can?t pass.

- The lack of chromatin decondensation of spermatozoon or oocyte after it has entered in the oocyte.

ICSI failure

The total fertilization failure has been recorded in fewer cases when using the ICSI procedure compared with those in which the conventional in vitro fertilization procedure has been used, but it can still occur. In the ICSI procedure the initial steps of fertilization, that consist in the penetration of the oocyte by the spermatozoon, is overlooked. The failure of ICSI can often happen due to the processes that occur after this stage (the lack of chromatin decondensation of the oocyte, the spermatozoon or of them both and the incapacity to form pronuclei) .