Endometriosis often occurs inside the ovaries and this disorder can gum up the proper inner working of our reproduction system. In general, endometriosis can:
• Keep eggs from developing properly.
• Destroy much of the ovaries, which also disrupt egg production.
• Prevent the normal release of eggs by:
– Encasing them in scar tissue and endometriosis tissues.
– Disrupting the normal egg release mechanism.
• Cause immune responses that are detrimental to fertilization processes.
Ovarian endometriosis can be seen microscopically, it may bury itself deep inside or develop on the surface.
Endometriosis and egg development
Each stage of endometriosis affects egg development in different ways. On Stage I (minimal) and II (mild) endometriosis, there are different problems related to eggs production:
• Even with an IVF (in vitro fertilization) procedure, the implantation rate is low.
• Endometriosis at early stages affects egg quality, which can result in poor embryo quality.
It appears that early endometriosis stages cause worse effects on eggs development than Stage II and IV. It may not seem to make sense, but these are the reasons:
• Early stages of endometriosis are actually very active, as the endometrial tissue grows rapidly, additionally destructive enzymes, proteins and cells are produced. Abnormal cells and toxic substances can negatively affect egg development.
• Toxic substances affect both unfertilized and fertilized eggs inside the pelvic cavity.
• On later stages, endometrial tissues no longer grow and are less active metabolically.
At early stages, endometriosis can be treated with super-ovulation drugs, which stimulate follicles production and improve eggs quality.
Severity of endometriosis can be determined by how far it’s advanced, where it’s located and the amount of endometrial tissues. Stage III (moderate) and IV (advanced) are considered as severe and reduce the chance of successful pregnancy. These are how severe endometriosis can affect egg development indirectly:
• Anatomy distortion (scar tissue and blocked tubes).
• Loss of fingerlike projections (fimbriae) that help egg reach the fallopian tube.
• Reduction in ovarian volumes, which decreases the number of viable eggs.
Women with severe endometriosis can still be pregnant. In some cases, fertilized egg (embryo) can be planted into the uterus using the IVF procedure, thereby bypassing fimbriae and fallopian tubes. Using proper methods, these women have the same chance of having successful pregnancy than healthy women.
Endometriosis and ovarian reserve
It is commonly understood that endometriosis affects egg development negatively, especially during the early stages. But why women at later stages are still difficult to get pregnant? One significant reason is the reduction in ovarian reserve, which lowers egg production. Each woman has finite amount of eggs that can be produced throughout her whole reproductive life. If the ovarian reserve decreases due to endometriosis, we may have premature menopause and run out of eggs earlier than usual. This condition leaves you with far fewer viable eggs, in fact during a cycle no good eggs are available for a pregnancy.
How endometriosis reduces ovarian reserve can be explained by the following steps:
1. Endometrial tissues grow on the ovaries surface.
2. The endometrial tissue has monthly cycle of growth and shedding. The repeated bleeding and growth on the ovary surface can cause inflammation. As the result irritants and toxic materials are released.
3. Scar tissues have endometrial implants inside them. The implants grow into the ovary by following paths of least resistance, instead of spreading on the ovaries surface.
4. This process literally destroys the ovary surfaces that house primordial follicles, leaving the patient with less ovarian tissues and fewer follicles.
Scar tissues that cover the ovary surfaces are fibrous and tough. As it spreads across the ovary surfaces, endometrial implants take the path of least resistances and grow into the inside of the ovary (the softer stroma). Consequently endometriosis or chocolate cysts form on the ovary surfaces. It is called chocolate cysts because of brown-colored liquids, which are made from old tissues and blood inside the cyst. Endometriosis cysts are not actually cysts, because fluid in a normal cyst comes from the structure lining. Endometrioma walls are different with normal ovary walls because they are a combination of endometrial tissue, inflammatory materials and fibrous tissues, none of which contain fluid.
When the endometrioma expands, the following process can occur:
1. The endometrioma compresses and squeezes out normal ovarian tissues.
2. The compressed ovarian tissues can have disrupted functions. In severe cases they stop functioning and die.
3. When ovarian tissues stop functioning, the hormonal ovary environment is no longer normal, which affects the menstrual cycles and cause menopause to comes earlier.
After an endometriosis surgery, the ovarian tissues can also lost, anytime endometrial tissues are removed, other scarring and adhesions can happen, as the result surgery can still harm the ovary. Adhesions glue the ovary to the uterus, fallopian tubes and intestines, so during a surgery, the surgeon must be especially careful to avoid unintended damages. Sometimes, an organ must be sacrificed and the ovary will be chosen because, unlike intestines, for example, it has least importance for normal body functions. Injuries to other structures can cause ectopic pregnancy, life-threatening infection and excessive bleeding. A prudent surgeon will be conservative and try to avoid tubal, bladder and intestinal damages. Even when the surgery is performed carefully, some pieces can still removed from the ovary. When chocolate cysts are removed, the surgeon needs to cut some part of normal ovary tissues to ensure thorough removal, which invariable damages the ovary surfaces. Although the surgeon doesn’t need to remove any tissues, suturing the ovary back can destroy some parts of the ovary. The loss of even a small amount of ovary tissues can decrease ovaries reserve and in severe cases, it can lead to infertility. Before a surgery, it is important to know what surgery methods that will be used. Let your doctor explains about the pros and cons of each option. In the end, it’s not the surgeon’s body and you should make the best decision possible.