The exact mechanisms by which endometriosis causes infertility are not fully understood. Dr. Karen Amaniampong has provided some insight for some of the most common evidence to suggest how it occurs:
Anatomical distortion in the pelvis
The shape and the position of the uterus is crucial to allow for successful fertilisation and pregnancy. Endometriosis can cause anatomical distortion in the pelvis due to the presence of sticky lesions that can merge together to form adhesions or scar tissue. This can alter the shape and the position of the uterus, therefore disrupting the release of the oocyte or making it difficult for sperm cells to travel to the oocyte.
Ovarian dysfunction
The ovaries are the most common site for endometriosis lesions in the pelvis. This directly affects the quality, number, and release of oocytes. Ovarian dysfunction can lead to a reduction in the number of follicles that grow into an egg cell, which can make it difficult to release an egg capable of being fertilized.
Immune dysfunction
As the endometrium lining breaks down during menstruation, inflammatory factors are naturally released. In endometriosis, the lesions also bleed since they are composed of tissue similar to the endometrium. This causes more inflammation to occur, which becomes dysfunctional and damages even the healthy tissue. This inflammation cause high levels of stress on the follicles, reducing their quality. Increased inflammation can also lead to increased preterm birth and increase the risk of pre-eclampsia. A problem with the immune system may make the body unable to recognize and destroy endometrial-like tissue that's growing outside the uterus.
Endometrial receptivity
This refers to the time during a menstrual cycle when the endometrium is most favourable for embryo implantation. Endometrial receptivity can be impacted by imbalances in hormones, such as oestrogen and progesterone. These hormones control the thickness of the endometrium, which is required for embryo implantation. Endometriosis causes these hormones to be imbalanced, and this can affect the endometrium’sability to adhere to the embryo, causing fertility issues.
Muscle contractility
If endometriosis lesions contort the shape of the uterus, it can impact its’ ability to contract correctly. This can prevent proper sperm or oocyte transportation. If pregnancy has occurred, it can still disrupt the ability to carry the baby to term by increasing the risk of preterm birth and caesarean section.
In our next article, we explore how you can navigate infertility caused by endometriosis: How to manage with infertility struggles
