Is endometriosis hereditary?

What is Endometriosis?

Endometriosis is a disease of the female reproductive system. It occurs when there is tissue resembling that lining of the uterus also called endothelium, located outside of the uterus. The normal uterine tissue responds to hormonal changes during the menstrual cycle and is shed if the woman does not become pregnant leading to menstruation. The uterine tissues outside the uterus in endometriosis also respond to the hormonal changes like the normal uterine endothelium, this will lead to bleeding outside the uterus.  As a result, there is often a resultant chronic inflammatory reaction that may result in the formation of scar tissue also called adhesions or fibrosis within the pelvis and other parts of the body where it is located. Based on where exactly they are found, they can be classified as:  superficial endometriosis which is found mainly on the pelvic peritoneum, cystic ovarian endometriosis which is found in the ovaries, deep endometriosis when it is found in deeper pelvic structures like in the recto-vaginal septum, bladder, and bowel. Finally, it can also rarely be found outside the pelvis like the vagina, vulva, and abdominal surgery scars.

Endometriosis affects roughly 10% (190 million) of reproductive age women and girls globally.

What Causes Endometriosis?

The causes of endometriosis are largely unknown, however, there are several theories or hypothesis on the possible causes as to why uterine tissue is found outside the uterus.

One hypothesis suggests that during menstruation, a process called ‘reverse or retrograde menstruation’ occurs where there is backflow of blood containing endometrial cells through the fallopian tubes, into the pelvic cavity, where they can implant and grow.

 The second hypothesis suggests that stem cells give rise to the disease, and then it spreads to the other sites like cancer cells through the blood and lymphatic vessels.

 A last hypothesis proposes that endometriosis can be a form of cellular metaplasia, where cells outside the uterus transform to endometrial-like cells and begin to grow.

It has also been proposed that during uterine surgeries, uterine tissue can be inadvertently directly implanted in other sites by the surgeon.

Research is still ongoing to exactly give a cause of endometriosis, however, what is known is that the hormone oestrogen has been reported to worsen the symptoms of endometriosis.

What are the Symptoms of Endometriosis?

The most common symptoms of endometriosis are pain and infertility.

The pain of endometriosis can be very severe and debilitating and can interfere with daily activity. The exact cause of pain in endometriosis is unknown even though there are still several theories. However, the pain has been known to reduce after pregnancy and menopause in some cases.

Infertility is another common symptom of endometriosis. About 25 to 50% of infertile women have endometriosis, and 30 to 50% of women with endometriosis are infertile.

Other symptoms of endometriosis include:

Painful or even debilitating menstrual cramps (60 to 80% of cases), Pain during or after sex (deep dyspareunia) (occurs in 40 to 50% of cases), chronic pelvic pain (40 to 50% of cases), Pain in the intestine or lower abdomen, Painful bowel movements or painful urination during menstrual periods, very heavy menstrual periods, and Premenstrual spotting or bleeding between periods (10 to 20% of cases).

Depression and anxiety also occur in endometriosis as a result of the greatly reduced quality of life caused by the symptoms.

Classification of Endometriosis

There are many classification systems of Endometriosis, however, the most widely used is the revised classification system by the American Society for Reproductive Medicine based on severity. It is classified as: Stage 1 (Minimal Endometriosis), Stage 2 (Mild Endometriosis), Stage 3 (Moderate Endometriosis), and Stage 4 (Severe Endometriosis)

Is Endometriosis Hereditary?

Despite the fact that the exact cause of endometriosis is unknown and aetiology has been proposed to be multifactorial, research reports that there may be a genetic component to the disease as there has been demonstrable familial clustering of the disease even though it does not appear to be inherited in a simple Mendelian mode. First degree relatives of affected women are 5 to 7 times more likely to have surgically confirmed disease. Cousins are also affected. Generally, endometriosis has been reported to be more common among related women, suggesting a genetic and hereditary component to the disease.

It is also important to note that familial clustering does not always reflect a genetic etiology. This could represent other risk factors for the disease which cluster in the family, like life-style and diet.

Treatment options of Endometriosis

There is no exact treatment for endometriosis. Management options are targeted towards ameliorating the symptoms. Treatment can be with medications and/or surgery depending on symptoms, lesions, desired outcome, and patient choice.

Early diagnosis and commencement of treatment has also been associated with better outcome. If you have the above symptoms, do see a gynecologist for proper evaluation.