Endometriosis is a common condition among women of reproductive age. While you may think of endometriosis primarily as a condition that affects the anatomical structure of the uterus, fallopian tubes and ovaries, inflammation - a defining feature of endometriosis - also negatively impacts the quality of eggs. Let's take a look.

What is inflammation?

Inflammation is the body’s natural way to remove the cause of damage and impacted tissue, fight infections and start the process of tissue repair. When cell damage occurs, blood flow to the affected area and the permeability of the blood vessels increase, so that fluid and immune cells like neutrophils and macrophages can access the affected tissue and fight potential infections. This is why we experience acute inflammation as swelling, heat, pain and so on.

While acute inflammation is a natural and useful function of the body’s immune and vascular systems, chronic inflammation can have negative effects on female fertility, as well as overall health of men and women. Many chronic diseases, such as diabetes and cardiovascular diseases are conditions of chronic inflammation, where the inflammation lasts for months and years. In chronic inflammation, the cycle of tissue destruction and repair occurs continuously and simultaneously, resulting in permanent tissue damage.

Inflammation and endometriosis: Fertility impact through egg quality

Endometriosis is an estrogen-dependent inflammatory disease characterized by the presence of endometrial glands and stroma outside the uterine cavity.  When the endometrium - the lining of the uterus - grows outside of the uterus, the endometrium bleeds with the woman’s monthly cycle, just as the endometrial tissue located properly inside the uterus does. This bleeding outside the uterus is perceived by the immune system as an injury that needs repair, leading to inflammation.

Endometriosis can impact female fertility structurally, as well as through inflammation. For example, when endometriosis damages the fallopian tubes, it can impede the movement of the ovulated egg through the fallopian tubes, preventing fertilization. When endometriosis invades the ovarian tissue, substances involved in the inflammatory process in the ovaries can affect the quality of eggs. A study published in Gynecologic Endocrinology in 2019 found that IVF/ICSI patients with endometriosis were more likely to have lower-quality, immature oocytes than patients without endometriosis.

All told, somewhere between 30 and 50% of women with diagnosed endometriosis experience infertility. Reassuringly, however, studies have found that women with endometriosis have outcomes comparable to women without, when they receive fertility treatments like IVF.

 A 2019 study published in the journal Fertility and Sterility reported similar results: women with endometriosis had significantly fewer antral follicles and ended up with fewer mature oocytes after ovarian stimulation for IVF. Investigating the effects of local inflammation on the granulosa cells (the cells that surround, support and nurture the growing eggs in the ovaries), the authors of this study hypothesized that the inflammation from endometriosis negatively affects oocyte maturation and egg quality by altering the expressions of genes in the granulosa cells.

More studies are needed to understand the cellular and molecular mechanisms, but current evidence appears to support the notion that chronic inflammation of endometriosis reduces both the quantity and quality of eggs.

Symptoms and diagnosis of endometriosis

Endometriosis is an unusual condition where severity of symptoms doesn’t always correlate with severity of the disease. Some women have late-stage endometriosis with virtually no symptoms while others have severe pain with what appears to be a mild case. Keep an eye out for these symptoms - these are signs that you may have endometriosis and should see a doctor:

• Severe menstrual cramps that are unrelieved by non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen
• Excessive bleeding, such as heavy periods, periods lasting longer than seven days or bleeding between periods
• Pain during intercourse
• Long-term pain in the pelvis and lower back
• Other symptoms, especially during menstrual periods, such as nausea and vomiting, fatigue and gastrointestinal issues

An experienced OBGYN doctor may be able to diagnose endometriosis simply based on your history, especially the location and timing of the pain. Pelvic exams, ultrasounds and MRIs are sometimes used to visualize and diagnose endometriosis. Diagnostic laparoscopy has become somewhat less common in recent years, although a laparoscopic surgeon can also remove the endometriosis at the same time as the diagnosis.

Treatment options for endometriosis and fertility considerations

While surgery can be a life-changing treatment for women with severe symptoms, fertility experts have a word of caution: Endometriosis surgery may not be the best for women who are planning to have children. Surgical removal of endometriosis can damage reproductive organs, even when done conservatively. Especially if a significant portion of an ovary is removed, immature eggs waiting for their turn in the ovary are also removed.

For this reason, for women who are still building their families, doctors may instead prescribe pain medications and/or hormonal medications to manage the symptoms. Some doctors, like the authors of this 2015 review in Seminars in Reproductive Medicine, even recommend fertility preservation for reproductive-age women before undergoing endometriosis surgery.

Anti-inflammatory lifestyle for better egg quality

From the egg quality standpoint, it is equally important to reduce inflammation. Your doctor may prescribe medications to target inflammation, or suggest lifestyle changes to help your body return to the normal level of inflammation:

• Adopting an anti-inflammatory diet - a pattern of eating that is low in foods that contribute to inflammation (refined carbohydrates, red meats, etc.) and high in those that are known to help bring down inflammation (olive oil, leafy vegetables, nuts and fatty fish, for example) - has been shown to improve various inflammation-related conditions.
• Taking antioxidant supplements like CoQ10, Vitamin C and Vitamin E, and/or focusing on antioxidant-rich foods may also help support egg quality by protecting and supporting a cell’s powerhouse, the mitochondria.
• DHEA, a fertility supplement often recommended for egg quality, may not be suitable for women with endometriosis, because some of the DHEA is converted into estrogen in the body, which can fuel endometriosis' growth.
• Other lifestyle decisions, like getting enough quality sleep and being active, have been shown to reduce inflammation. Being active is easier said than done when you are dealing with endometriosis pain, but when manageable, exercise can be an effective way to manage pain from both physical and psychological standpoints.

Talk to your doctor, if you suspect inflammation or endometriosis

The inflammatory aspect of endometriosis and its effects on egg quality is still an evolving area of research. However, evidence is emerging that inflammation reduces egg quality in women with endometriosis, with fertility implications. The good news is that there are medical and lifestyle interventions to reduce inflammation and mitigate its negative impact on egg quality.

As always, if you suspect you have endometriosis or inflammation might be playing a role in your fertility struggles, consult your doctor to get a treatment recommendation suited to your particular situation.