Why does endometriosis cause pain and health problems?

Growths of endometriosis are benign (not cancerous), but they still can cause many problems:

  • Uterine or ovarian cancer: Even though a diagnosis of endometriosis does not automatically mean that you are going to get cancer, sometimes the displaced endometrial cells become cancerous.
  • Infertility: Researchers have found that in cases of infertility among young women, 25 to 50 percent are due to endometriosis. When your displaced endometrial tissue swells and bleeds, it can cause scar tissue and cysts to develop. This extra matter can sometimes block some of the reproductive organs and processes. It is possible to become pregnant while you have endometriosis, but it can be a very long process. Once you become pregnant, your endometriosis symptoms will likely stop temporarily.
  • Abdominal pain: Endometriosis often causes abdominal pain because it involves endometrial tissue spread throughout the abdominal area. When you begin to menstruate, your displaced endometrial tissue begins to swell and bleed excessively. This aggravates all part of your abdominal area, resulting in intense cramps and heavy bleeding.

To see why these problems occur, it helps to understand a woman's menstrual cycle. Every month, hormones cause the lining of a woman's uterus to build up with tissue and blood vessels. If a woman does not get pregnant, the uterus sheds this tissue and blood. It comes out of the body through the vagina as her menstrual period.

Patches of endometriosis also respond to the hormones produced during the menstrual cycle. With the passage of time, the growths of endometriosis may expand by adding extra tissue and blood and the symptoms of endometriosis often get worse.

This answer is based on source information from The National Women's Health Information Center.

Even mild forms of endometriosis can cause profound infertility. The good news is that endometriosis is very treatable, and most women conceive after it is diagnosed.

Complications from endometriosis include difficulty getting pregnant, internal scarring, ovarian cysts and chronic pelvic pain. Not all women experience these issues, and early treatment can help prevent many of these complications.

There is no data showing endometriosis causes an increased risk for cancers overall, however, there is evidence that women with endometriosis are slightly more likely to develop ovarian cancer. The chance is small enough that screening tests are not recommended in patients with endometriosis as their only risk factor. Treatment with hormone therapy decreases the risk for some cancers and increases the risk of others. Talk to your doctor about whether he or she recommends hormone therapy for you.

Endometriosis can adversely affect fertility at many levels. Not only can endometriosis distort the pelvic anatomy and make egg pick-up by the fallopian tube more difficult, but this disease can also adversely affect egg quality, egg numbers, embryo development and implantation rates. While women in the general population have been reported to have a 15 to 20 percent chance of pregnancy per month, those with endometriosis may have a 2 to 10 percent chance of pregnancy per month. The time to pregnancy is increased in women with endometriosis who are trying to conceive with natural cycles.

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Dr. Kevin W. Windom, MD
OBGYN (Obstetrician & Gynecologist)

Endometriosis is caused by numerous different factors, but the most common theory of endometriosis is the retrograde menstruation theory. Every month when a patient has a menstrual cycle, some of the blood flows backwards through the uterus and out the fallopian tubes. This retrograde menstruation can cause endometrial lining cells to implant in different places in the pelvis or abdomen. When endometrial tissue implants start to grown in the abdominal cavity, they can expand and contract with the normal hormonal variations that a woman has each month. This expanding and contracting can cause pain as well as the body realizes this is a foreign object and sends out an immune response to combat this abnormality. Both of these issues could cause pain for the patient. The endometrial lining tissues can also form cysts as well as can trap blood in these cysts which will cause pain. The most common sites for endometrial implantation is in the posterior vagina, cul-de-sac, and this area is notorious for causing vaginal pain as well as pain with intercourse. The endometrial tissue can also form a collection of fluid that is called an endometrioma, and these are most commonly seen on the ovaries.

It is very well known to clinicians that the amount of endometriosis that a patient has does not always correlate to the pain that they are experiencing. In my clinical practice, I have seen patients with stage 1 endometriosis that have debilitating pain requiring multiple surgeries and narcotics. I have also had patients with stage 4 endometriosis (the highest stage), and these patients have very little pain but have severe infertility.

In my clinical practice, I have seen patients with irritable bowel syndrome caused by endometriosis as well as chronic constipation caused by endometriosis. I have also seen patients with endometriosis implants that have implanted near their lungs and have caused a pneumothorax (collapsed lung) as well as endometriosis is one of the more common causes of women missing work due to severe pelvic pressure, pelvic pain, and changes with their menstrual cycle.

Patricia Geraghty, NP
Women's Health

There is data showing a slight increase in risk of ovarian cancer in women who have endometriosis. One study showed an increased risk of 32 percent. This needs to be translated into absolute numbers to be better understood. The overall risk of ovarian cancer before age 65 years age is 8 women in 1000. Adding 32 percent risk gives us 10 women in a thousand. The same study showed that 10 years of using oral contraceptive pills reduced risk or ovarian cancer by 80 percent.

While the connection between endometriosis and infertility is not clearly understood, advanced-stage endometriosis makes it very difficult for the egg and sperm to reach each other.

Endometriosis is a disease in which endometrial tissue is found outside of the uterus, typically on the ovaries, fallopian tubes, bladder and bowel. It occurs in reproductive age women.

Treatment of early-stage endometriosis doesn't seem to make a difference in pregnancy rates, but knowing you have it may influence your choice of reproductive technology. Be sure to report these symptoms to your healthcare professional: painful menstrual cramps that get worse over time, extremely heavy menstrual flow, diarrhea or painful bowel movements (especially around the time of your period) and painful sexual intercourse.

Endometriosis can affect fertility. Inflammation in the abdomen may lead to infertility and that treatment may increase your odds of getting pregnant.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.