Research based on the Nurses’ Health Study II has shown that certain types of dietary fats may increase the risk of endometriosis, while other types are associated with a lower risk. The study analysed 12 years of data, which equated to 568,153 person-years. Nearly 1200 cases of diagnosed endometriosis occurred over this time.

The women who consumed the most long-chain omega-3 fatty acids were 22 per cent less likely to be diagnosed with endometriosis compared to the women who consumed the least. Long-chain omega-3 fatty acids are the “good” fats found in oily fish and are associated with maintaining cardiovascular health.

Conversely, those women who consumed the most trans-unsaturated fat were 48 per cent more likely to develop endometriosis than those who consumed the least. Trans-unsaturated fats are commonly found in deep-fried foods, some take-away foods and baked goods such as pastries, cakes and biscuits.

The authors of the study suggest that increasing long-chain omega-3 fatty acids intake and decreasing trans-unsaturated fats intake could reduce a women’s risk of developing endometriosis, potentially making it the first indentified modifiable risk factor.

According to Jean Hailes gynaecologist Dr Elizabeth Farrell, “Women who have an unhealthy weight are more likely to have more oestrogen, which if they have a tendency to endometriosis would stimulate growth of the endometriosis cells. Avoiding animal fats and trans-unsaturated fats and having more omega-3 fatty acids is important for health and wellbeing. This is an interesting observational study showing once again that healthy eating with appropriate foods/oils may have a positive effect on an illness or reduce its risk. More research however is needed to see how dietary oils may affect endometriosis cells.”

Content updated May 4, 2010

FAQ

1. What’s the difference between having heavy periods and endometriosis?

Some women have heavier or more painful periods than others, however this does not mean they all have endometriosis. Endometriosis occurs when the tissue normally lining the uterus (the endometrium) is found outside the uterus. The misplaced tissue commonly grows on the fallopian tubes, the ovaries or the tissue lining the pelvis. Over time, it can develop into cysts or become sticky, causing the surrounding tissues and organs to stick together and scar.

2. How do I know if I have endometriosis?

Symptoms include:

• Lower abdominal, back or pelvic pain, during or before your period
• Heavy periods
• Pain at other times
• Tiredness, bloating, mood changes, infertility

Having to take time of school or work is a good indicator of the severity of the symptoms.

Endometriosis can only be diagnosed accurately by a laparoscopy. This is an operation performed under general anaesthetic, where a small telescope is inserted into the abdomen through a cut in the belly button. Sometimes an ultrasound can also show signs of endometriosis, but only if the endometriosis forms a cyst in the ovary.

3. What causes endometriosis? Is it hereditary?

We don’t know what causes women to develop endometriosis. There are some examples of families where different generations of women are affected, so a genetic or hereditary factor may be involved.

4. How do I cope with a disease that has no cure?

The following emotional effects can all impact on your quality of life:

• Living with a potentially chronic condition
• Ongoing pain or other symptoms
• Increased anxiety or moodiness
• Painful intercourse which interferes with your relationship
• Difficulty getting pregnant

5. I have been diagnosed with endometriosis. What are my chances of getting pregnant?

30 per cent of women with infertility have endometriosis. Currently, the most effective treatment is surgical removal of tissue, usually by laparoscopy. The chances of pregnancy seem to be best immediately following surgery. On a positive note, many women report that their endometriosis is temporarily ‘cured’ when they become pregnant (because they are no longer having their period).

6. Will pregnancy cure endometriosis?

Symptoms of endometriosis appear to improve with pregnancy. This is thought to be due to decidualisation (higher progestogen levels cause the endometriosis to regress); however, the long term effects of endometriosis are unclear. In a small study of 23 cases (McArthur & Ulfelder, Obstet Gynecol Surv. 1965;20(5):709), the endometriotic lesions enlargened during the first trimester and then regressed as the pregnancy continued.

7. Will endometriosis affect my pregnancy or delivery in any way?

Endometriosis is diagnosed in a third of women presenting for investigation of infertility. Severe endometriosis can interfere with getting pregnant but in mild cases the reasons for difficulty falling pregnant are uncertain. Endometriosis does not appear to affect pregnancy and delivery.

8. Can endometriosis lead to cancer?

Very rarely, cancer has been diagnosed in endometriosis tissue. It is recommended if a woman is diagnosed with an endometrioma or chocolate cyst in an ovary on ultrasound and there has been no histological diagnosis (what the cells look like under a microscope) of endometriosis, that the cyst be removed so that a histological diagnosis can be made.

9. How does endometriosis affect the bowel?

Endometriosis can rarely develop on the outside of the bowel and may, in time, infiltrate or develop into the bowel, causing pain, bleeding and, if in the lower pelvis near the uterus, dyspareunia (pain with intercourse).

10. Will my endometriosis go away after menopause?

Usually endometriosis does resolve after menopause, however rarely it may recur on hormone replacement therapy (HRT), or even more rarely spontaneously.

11. Do women with endometriosis experience menopause any differently?

If menopause occurs naturally at the expected age, the experience is not different from other women without endometriosis. Menopause experience is individual and ranges from no symptoms to severe symptoms. If a woman has had a surgical menopause i.e. her ovaries have been removed with or without her uterus, then severe symptoms will be experienced unless HRT is commenced soon after surgery.

12. If my symptoms aren’t affecting my quality of life, is surgery necessary?

If you already have a definitive diagnosis of endometriosis and your symptoms are not affecting your life or you are managing them effectively, surgery may not be necessary.

13. I am only 19 years old, is it wise for me to start having surgeries at such a young age?

If you have severe pain and your life is impaired, endometriosis or the reason for the pain needs to be diagnosed initially and laparoscopy is the only way to make this diagnosis. Once the diagnosis is made, further surgery may not be necessary as the symptoms may be able to be controlled by medications such as the combined oral contraceptive pill.

Discuss all your symptoms with your GP and ask to be referred to a gynaecologist with a special interest in endometriosis. You may like to see a counsellor or psychologist to discuss your feelings and deal with emotional issues.