Endometriosis Overview

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Endometriosis Overview

Updated: 8-November-2022


Endometriosis is a common yet complex gynaecological inflammatory disease characterised by the growth of endometrial-like tissue outside the uterus (endometrium). As a chronic inflammatory disease, it is also found more often in women with other inflammatory diseases (interstitial cystitis, pelvic inflammatory disorder, irritable bowel syndrome).

Globally endometriosis affects around 190 million women worldwide, impairing quality of life both physically and mentally. These women, including some adolescents, are predominantly of reproductive age, of which 30 to 40% will suffer from infertility and or chronic pelvic pain.

Male partners can have a positive effect on the symptoms of pain and psychological health of their partner, simply by taking an interest in their condition, and accompanying them to appointments

Source: Facchin F, et al. (2021)

Common locations for endometriotic lesions include:

  • Ovaries
  • Uterine ligaments
  • Pouch of Douglas
  • Bladder wall
  • Bowel serosa
  • Fallopian tube mucosa
  • Myometrium

Clinically speaking endometriotic lesions are classified into 3 subtypes, based on location and histopathology examination.

  1. Superficial endometriosis occurs on the uppermost layer of soft tissues of the peritoneum or internal organs.
  2. Deep infiltrating endometriosis which invades the muscular muscles of the organs.
  3. Ovarian endometriotic cysts, also known as endometriomas (or chocolate cysts), which are attached to the ovaries.

    The size and location of these, along with any adhesions, determines the severity of endometriosis according to the rASRM (revised American Society for Reproductive Medicine), which is the most common classification system for endometriosis.

    The rASRM scoring system classifies endometriosis into 4 types:

    Stage 1 – Minimal Endometriosis
    Stage 2 – Mild Endometriosis
    Stage 3 – Moderate Endometriosis
    Stage 4 – Severe Endometriosis

    However, this scoring system has well known limitations, primarily poor predictive power of pregnancy following surgery, compared to alternative systems.

    In fact, the severity of pain or likelihood of infertility does not correlate with the rASRM classification of endometriosis
    Source: Zondervan K T, et al. (2020)

    In addition, the endometrium of women with endometriosis differs significantly. Increased inflammation, altered microbiome composition, resistance to progesterone and in situ estrogen production, is believed to affect embryo fertilization and or implantation.

    Whilst subtle Fallopian tube abnormalities found in 70.9% of women with endometriosis, hinders the transport of the oocyte and fertilisation.

    Source: Zheng X, et al. (2021)

    Although studies show women with endometriosis are significantly more likely to have blocked fallopian tubes. This finding is true even for infertile women diagnosed without endometriosis. Unsurprisingly the risk of blocked fallopian tubes is higher according to the severity of endometriosis (rASRM stage III or IV).

    Symptoms of Endometriosis

    The most common symptoms of Endometriosis are:

    • Chronic pelvic pain or back pain.
    • Dysmenorrhea (painful periods). Cramping and pelvic pain worsens during the menstrual cycle. Although pelvic pain is quite common during menstruation, that associated with endometriosis is worse and can even prevent one from performing daily activities.
    • Dyspareunia which is pain during or after sexual intercourse.
    • Pain with urination, full bladder or bowel movements.
    • Dyschezia (constipation)
    • Menorrhagia (excessive bleeding during menstrual period). Bleeding during urination or bowel movements may also occur.
    • Catemenial pneumothorax (recurrent collapsed lung) just before or after the start of menstruation.
    • Infertility

    Only a small portion of women (2-25%) report experiencing all 3 (pelvic pain, dysmenorrhea, dyspareunia) of the most common pain symptoms associated with endometriosis.

    Source: Becker K, et al. (2021)

    Other symptoms, particularly during menstruation, such as bloating, nausea, diarrhoea, constipation and fatigue may also be present. Although the severity of these symptoms is not an indication of the severity of the disease. However, headaches are more common in women with severe endometriosis.

    In some women, the condition can severely impact their day-to-day lives and cause depression. In these circumstances, it is vital to seek help from a medical professional.

    Misidentification of endometriosis with other conditions can also occur due to the similarity of symptoms. For example, Irritable Bowel Syndrome (IBS) is a very common condition that also causes abdominal cramping along with spells of diarrhea/constipation.

    In fact, between 6% to 43.3% of women are asymptomatic (no symptoms) with the presence of the endometriosis lesions only found while undergoing abdominal surgeries for reasons not linked to endometriosis. Interestingly, the absence of pain is more likely in women with severe endometriosis (Stage IV).

    Risks Associated with Endometriosis

    Women diagnosed with endometriosis are at higher risk of other diseases.

    These include:

    • Ovarian cysts
    • Uterine fibroids
    • Pelvic inflammatory disorder
    • Infertility or delay in conceiving
    • Complications during pregnancy (venous thrombosis, pre-eclampsia, placenta previa, placental abruption, caesarean section)
    • Interstitial cystitis
    • Cystitis / Urinary Tract Infection
    • Irritable Bowel Syndrome
    • Constipation / dyschezia
    • Skin issues (eczema and dermatitis)
    • Mental illnesses (stress, anxiety, depression)
    • Fatigue / chronic fatigue syndrome / neurasthenia
    • Restless Leg Syndrome
    • Fibromyalgia
    • Headaches
    • Ovarian / tubal cancer
    • Endometrial cancer
    • Breast cancer
    • Skin cancer (melanoma)
    • Thyroid disorders
    • Autoimmune disorders (Systemic Lupus Erythematosus, Rheumatoid Arthritis, Ankylosing spondylitis, Sjogren’s syndrome, Multiple Sclerosis)
    • Coeliac disease

    Although more research is continually being done understanding the link between endometriosis and comorbidities, the underlying theme is diseases of an inflammatory nature.

    Causes of Endometriosis

    The exact cause of endometriosis is still unknown, however there are 5 main theories:

    • Retrograde menstruation
    • Coelomic Metaplasia
    • Embryonic Rests
    • Lymphovascular metastasis
    • Stem Cell Origin
    • Low testosterone

    Diagnosis of Endometriosis

    See a doctor if you have any typical symptoms of endometriosis. Preferably someone experienced with endometriosis and similar conditions to minimise a potential delay in diagnosis and self-doubts.

    Dismissal of symptoms by doctors contributes to reduced self-esteem and depression.
    Source: Bontempo A C, et al. (2021)

    The doctor will then talk through your symptoms and signs before recommending some tests.

    Treatment of Endometriosis

    A cure for endometriosis is yet to be found however several treatment options, directed towards relieving the symptoms, increasing your fertility and improving quality of life are available.

    Your Doctor will discuss with you the various treatment options for endometriosis which are broadly categorised as:

    • Non-fertility specific treatment
    • Fertility specific treatment


    The best age to get pregnant with endometriosis according to the Endometriosis Fertility Index scoring system is before 35 years of age.

    Women between 35 and 40 years of age with endometriosis, have 1 point deducted in this scoring system, while women older than 40 lose 2 points, which mirrors the natural decrease in fertility of women without any fertility related conditions.

    Range of fertility rates among women worldwide according to age

    This seemingly null effect of aging on endometriosis is supported by other studies, which suggest the growth of endometriosis lesions stops almost entirely once a woman reaches adulthood (~24y.o).

    This suggests any future preventative treatments, will most likely begin early on during adolescence.

    Recurrence of Endometriosis

    The normal rate of recurrence following surgery is high in the majority of cases other than abdominal wall endometriosis. Several studies show recurrence rates above 20% one-year post-surgery, especially among Stage III and IV endometriosis.

    Interestingly the same studies also showed that postoperative hormonal treatment and or pregnancy was associated with a significantly reduced risk of recurrence.

    While the risk of endometriosis recurring post-surgery, among women who undergo ovarian stimulation cycles, was found not to be any higher than normal.

    Recurrence of pain post-surgery is linked to the activation of neurogenesis and reduction in apoptosis (programmed cell death).

    Source: Radzinsky V, et al. (2020)


    Causes of Endometriosis

    Causes of Endometriosis

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    Diagnosis of Endometriosis

    Diagnosis of Endometriosis

    See a doctor if you have any typical symptoms of endometriosis. Preferably someone experienced with endometriosis and similar conditions…. Read more

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