It is interesting to know that = the Endometrium (lining of the womb) in women with polycystic ovary syndrome during the window of implantation is different from non-polycystic ovaries patients.
Implantation occurs during a limited period between the 20th and 24th days of the menstrual cycle, known as “window of implantation”. This process involves a com-
plex sequence of events that is crucial to establish a pregnancy. Many molecular mediators, under the influence of ovarian hormones, have been postulated to be involved in this fetal-maternal interaction. Morphofunctional alterations during this period may prevent or hinder the implantation. For this reason, the study of the endometrium at this phase is important to improve the mechanisms involved in the maternal-embryonic interaction.
Researchers have shown that in PCOS, overexpresses androgen receptors ( male hormone) and fails to regulate the ER-α (estrogen receptor, α) in the window of implantation. Research has shown PCOS has other common features in addition to hyperandrogenism (high male hormones) and ovulatory dysfunction that is not included in the diagnostic criteria already established, such as abnormal secretion of gonadotropins, insulin resistance and metabolic abnormalities (dyslipidemia). Increased expression of AIBI coactivators (nuclear receptor coactivator 3) of the estrogen receptor and TIF2 transcriptional intermediary factor 2) may enhance the estrogen activity in endometrial cells in PCOS.
Current research is not clear whether there is an endometrial dysfunction in PCOS, regardless of progesterone action. Some studies indicate that the endometrial process, including cell proliferation, differentiation and response to a biological stimulus, could be affected by other factors such as cytokines and growth factors, explaining in part the poor reproductive outcomes in this group of women.
The exact mechanism of implantation failure is still poorly understood, particularly in diseases such as PCOS. Although the quality of embryos is an important determinant, the lining of the womb has an unquestionable contribution to the success of pregnancy.
(Reference: Lopes et al Endometrium in women with polycystic ovary syndrome during the
window of implantation 2011)