Genital tract diseases

Some examples of diseases that may compromise the fertility are endometriosis, uterine fibroids, and neoplasms by disturbing the characteristics and morphology of the genital tract.

Endometriosis

Endometriosis is a gynecological disorder defined by the growth of endometrial tissue outside the uterus, outside its inner layer. This could occur in the ovaries and Fallopian tubes, in the bladder or bowels, and, rarely, in locations such as lungs, skin or brain.
 
When this endometrial tissue grows inside the muscular layer of the uterus, or miometrum, this disorder is known as adenomyosis

Just as in the uterus, this endometrial tissue responds to hormones released from the ovary, causing inflamation, pain and bleeding, leading to a decreased fertility.

Some theories aim to explain this infertily lead by endometriosis. It is speculated to result from several factors:

If ovaries are affected…

Endometriosis may inhibit ovulation preventing the release of the oocyte.

If the Fallopian tubes are affected…

The oocytes capture might not be effective or the encounter with the spermatozoa might be prevented

If the uterus is affected…

Due to the resulting inflamation, endometriosis might prevent embryo implantation.

Overall…

The harsh environment caused by the endometriosis might affect the germ cells survival, preventing fertilization.

Uterine fibroids

Uterine fibroids are non-oncological tumors caused by an excessive growth of muscular cells inside the uretus. They can be classified depending on their location:

  • If they grow towards the uterine cavity they are named as submucosal (a).

  • If they grow on the uterine wall they are intramural (b).

  • If they grow on the outter edge of the cavity they are subserosal (c).

  • If they grow on the outter edge of the cavity and attach to the uterus through a strand of tissue, they are pedunculated (d).

Although the exact origin of these disease is still unknown, it has been associated to genetic and hormonal factors, since it has been reported an influence from the progesterone and estrogen, which affect the growth of these fibroids

They appear during the reproductive age, when the levels of these hormones are high. Once menopause is reached, this levels are strongly reduced and, thus, the fibroids.

In this situation, infertility is due to anatomical alterations; which may affect the germ cells movement or prevent implantation by:

      1. Obstructing the Fallopian tubes
      2. Disrupting the uterine cavity

This latter event occurs mostly due to submucosal myomas (c) since they grow inside the endometrium, inner layer of the uterus, and protrude towards the uterine cavity

Apart from its effect on the fertility, fibroids  may cause complications in the early stages of the pregnancy and provoke  spontaneous miscarriages by preventing the embryo’s adequate growth.
Other situations