The problem of infertility and oocyte quality in endometriosis

Endometriosis is a common chronic estrogen-dependent inflammatory disease that impairs a woman’s reproductive function. Subfertility in endometriosis is associated with genetic and anatomical factors, activation of pro-inflammatory cytokines, uterine dysperistalsis, impaired endometrial implantation capacity, reduced ovarian reserve, especially after surgical interventions for ovarian endometriomas, and possibly impaired oocyte and embryo quality.An analysis of current open databases PubMed, MEDLINE, Scopus, ScienceDirect, Cochrane Library showed that there is currently insufficient evidence to prove or disprove the negative impact of endometriosis on oocyte quality. The number of antral follicles, the number and quality of oocytes and embryos obtained, and the fertilisation rate in patients with endometriosis did not differ significantly in one group of studies, while in another group there was a significantly reduced ovarian reserve, oocyte yield and number of mature oocytes. Evidence suggests that oocytes obtained from women with endometriosis more often have altered morphology, they are characterized by failed in vitro maturation and lower mitochondrial content, morphological abnormalities in the cytoplasm, zona pellucida, and the first polar body in the cytoplasm compared to women with other causes of infertility. The lower number of metaphase II oocytes, the lower total number of embryos and high-quality embryos, and the lower cumulative clinical pregnancy rate may be associated with lower oocyte yield, although a clear clinical impact on pregnancy has not yet been confirmed. The lack of consensus is partly due to the use of different morphological parameters, indirect assessment methods, such as granulosa cell status, follicular fluid volume, etc., to assess oocyte quality, which makes it difficult to determine and compare the results of different studies.Conclusions. The problem of infertility in endometriosis is a complex and multifaceted one and requires further research to determine the influence of phenotype and stage of endometriosis, extent of surgical intervention, ovarian reserve, standardisation of the assessment of the qualitative characteristics of oocytes and embryos on reproductive outcomes.