What are Possible Factors to Cause Endometriosis?

Endometriosis is a medical condition which bothers many women. Women with endometriosis may have difficulty with getting pregnant, however, fortunately, this infertility problem doesn't occur on all.

Even endometriosis causes remain unknown, there're still some factors thought to be risk factors.

Genetic predisposition plays a role in endometriosis. Daughters or sisters of patients with endometriosis are at higher risk of developing endometriosis themselves; low progesterone levels may be genetic, and may contribute to a hormone imbalance. There is an about 10-fold increased incidence in women with an affected first-degree relative.

It has been proposed that endometriosis results from a series of multiple hits within target genes, in a mechanism similar to the development of cancer. In this case, the initial mutation may be either somatic or heritable.

In addition, there are many findings of altered gene expression and epigenetics, but both of these can also be a secondary result of, for example, environmental factors and altered metabolism. Examples of altered gene expression include that of miRNAs.

Except for genetic factor, aging brings with it many effects that may reduce fertility. Depletion over time of ovarian follicles affects menstrual regularity. Endometriosis has more time to produce scarring of the ovary and tubes so they cannot move freely or it can even replace ovarian follicular tissue if ovarian endometriosis persists and grows. Leiomyomata (fibroids) can slowly grow and start causing endometrial bleeding that disrupts implantation sites or distorts the endometrial cavity which affects carrying a pregnancy in the very early stages. Abdominal adhesions from other intraabdominal surgery, or ruptured ovarian cysts can also affect tubal motility needed to sweep the ovary and gather an ovulated follicle (egg).

Endometriosis in postmenopausal women does occur and has been described as an aggressive form of this disease characterized by complete progesterone resistance and extraordinarily high levels of aromatase expression. In less common cases, girls may have endometriosis symptoms before they even reach menarche.

Another possibility is that areas lining the pelvic organs possess primitive cells that are able to grow into other forms of tissue, such as endometrial cells. (This process is termed coelomic metaplasia.)

It is also likely that direct transfer of endometrial tissues during surgery may be responsible for the endometriosis implants sometimes seen in surgical scars (for example, episiotomy or Cesarean section scars). Transfer of endometrial cells via the bloodstream or lymphatic system is the most likely explanation for the rare cases of endometriosis that develop in the brain and other organs distant from the pelvis.