Failure in IVF is affected by several factors,
that the most important factor is the quality of the oocyte. The quality of the
oocyte can be controlled by mitochondria. Since the mitochondria provide the
energy necessary for the fertilization process, any mutation in them can affect
this process. The most important mutation in the mitochondrial DNA is the
4977-bp deletion which eliminates the genes involved in the respiratory chain,
As a result, it reduces cell energy. So they can lead to failure in fertilization.
The association of this deletion with many diseases has been proven, including
the study of Gashti and his colleagues who examined the 4977-bp mutations in the semen samples of varicocele patients. In this study, the
frequency of this mutation was found to be 81.66% of patients (19). Also,
in the study of Salehi and his
colleagues on the tissue of endometriosis, the frequency of these mutations was
60% and the association of these mutations with positive endometriosis was
reported positive (20). In our study, which was performed in the female blood
samples of IVF failure, the frequency of mutations of 4977 in patients and in
healthy controls was 48.07% and 34.62%, respectively, and the relationship
between this deletions and failure rate in IVF cycles was not significant.
Also, Chan et al. compared the two parameters of deletion and the age of the
patients in 155 unfertilized oocytes from 52 patients and the incidence of
deletions in these oocytes was 34.6%, and in women older than 35 years of age,
a higher incidence of these mutations was observed (21). In our study, despite
the relatively high frequency of 4977 mutations in people over 35 years of age,
compared to those under 35 years old, the association of these mutations with
age was not significant.
Therefore, as a general conclusion,
despite the relatively high frequency of in women with IVF failure, there was
no significant association between these mutations and the failure in IVF as
well as the age of subjects with failure in IVF in blood samples and it is
better to these mutations investigate in the oocytes of these patients.