endometriosis > endometriosis-intro > diagnosis-of-endometriosis > types-symptoms

Fertility HealthFertility Conditons
Fertility TreatmentsStart you fertility journey

Sites, Types & Symptoms

Endometriosis is a complex disease with a confusing variety of types, sites and symptoms. The condition is mainly, but not always, in the lower abdomen; there are three distinct types of endometriosis lesions, and pain is the main symptom. Diagnosis usually takes so long that experienced researchers have suggested that symptoms and infertility should diagnose it, and only 5 to 10% of cases are asymptomatic. i


A good understanding of the symptoms of endometriosis is crucial for personal control of the condition, and the symptoms include:

  • Chronic pelvic pain that’s typically worse during and after the period but can occur any time of the month
  • Painful periods (dysmenorrhea)
  • Pain during and after sex (dyspareunia)
  • Infertility
  • Pain on opening bowels
  • Urinary tract symptoms; mainly pain, urgency and frequency
  • Digestive problems

Menstrual cycle dynamics of women who have endometriosis are classically that:

  • They started at a younger age than normal
  • They’re relatively short (less than 28 days)
  • They can be irregular in cycle length

The menstrual bleeds (periods) of women with endometriosis are usually:

  • Heavy 
  • The blood is often thicker, darker and has clots
  • The periods sometimes stop and start

Period pains are typically:

  • Severe, fixed and cramping
  • Worse for pressure
  • Better for warmth

The pain can:

  • Extend down the legs
  • Refer into the lower back
  • Have an intense “dragging-down” nature

Additional symptoms that some women get include:

  • Blood in their urine or stools
  • Pain at ovulation
  • Abdominal pain during stretching and movement

The symptoms vary with the site of the lesions and types of endometriosis involved. While women in their 20s to 40s have the highest diagnosis rates, endometriosis is found in young girls, menopausal women, and men.

Sites of endometriosis

Endometriosis lesions have been found everywhere in the body, including the skin, lungs, and brain, and a potential complication of surgery is “scar endometriosis” at the incision site. However, the most common sites are near the uterus:

  • Ovaries
  • Fallopian tubes
  • The uterine ligaments that hold the uterus in place
  • The outside of the uterus


Other less common sites include the:

  • Bladder
  • Vagina and cervix or vulva
  • The lower part of the colon or the rectum

The location and the type of endometriosis involved plays a large part in the symptoms, diagnosis and treatment options. Endometriosis involves three main cell types, and there are three main types of endometriosis.

Types of endometriosis cell

Endometriosis is the abnormal location and behaviour of cells that usually form the “functional layer” of the womb (the endometrium). Because of this, the type of endometriosis and how it behaves depends on the three main cell types involved in the lesions:

  • Blood cells
  • Mucous cells
  • Connective tissue

The combination of these cells creates a soft, sticky and spongy surface designed to encourage implantation. Although they’re growing outside the womb, they still respond to changes in sex hormones, which means that endometriosis tissue can:

  1. Grow in the follicular phase
  2. Release mucus or form adhesions in the luteal phase
  3. Bleed during the menstrual bleed

Types of endometriosis

There are three main types of endometriosis, which all form “lesions” (tissue changes caused by injury or disease):

1. Superficial peritoneal lesions

These lesions are found on the surface of organs and vary according to the tissue types:

  • Brown or pigmented lesions that look like dark spots (from trapped blood)
  • Pale pink, white or transparent lesions on the surface of organs that secrete fluids (which can form fluid-filled blisters)
  • Interconnected “webs” of connective tissue can form and tie organs together

2. Endometriotic cysts

These are closed sacs of tissue and are also known as “endometriomas” or “chocolate cysts”.  They show up clearly on transvaginal ultrasound or MRI, which makes diagnosing them easier than relying on surgery, and endometriomas are:

  • The type of endometriosis found most often (17-44%)
  • They’re usually found in or on ovaries, with the left ovary involved twice as often as the right
  • They also occur in the space behind the uterus or bladder and the bowel
  • They’re fluid-filled with thick, dark, old blood


Endometriomas are large structures that interfere with crucial processes and contain toxic material; the potential consequences of endometriomas include:

  • Chronic pain, worse with pressure, intercourse and menstrual bleeds
  • Decreased ovarian function
  • Problems with ovulation and egg retrieval in IVF
  • Increased risk of premature ovarian failure (POF)
  • When the bladder or the tubes that drain urine from the kidneys to the bladder (ureters) are affected, they can cause urgency and pain, often around the period

3. Deep Infiltrating Endometriosis (DIE) 

Deep Infiltrating Endometriosis (DIE) is a distinct category of endometriosis in which lesions penetrate at least 5mm into the peritoneum (the lining of the abdominal space) or other organ tissues. 

DIE usually causes severe pelvic pain because of the damage caused and the lesions “binding” organs and structures together. There’s no consensus on why some lesions become DIE, but it’s been suggested a combination of genetic and environmental factors such as exposure to radiation or dioxins triggers the change. iii


Adenomyosis is a variation of endometriosis, where the endometriosis lesions invade the smooth muscle layer of the uterus. The endometriosis can form endometriomas which cause focal pain; the womb becomes larger (by about 30%) and tender. All of the painful associations with endometriosis apply to this condition, and there are possibilities of complications in pregnancy.

Stages of endometriosis

For reference purposes, there are four “Stages” for endometriosis, which describe where the lesions are. It was originally thought the disease would progress in a linear fashion through the stages, but it’s now known this isn’t the case for many women.

  • Stage I: Lesions are confined to the “Recto-Uterine Pouch” between the back wall of the uterus and the rectum
  • Stage II: Lesions are found on the cervix, penetrate the vaginal wall, and cause fibrosis and small cysts
  • Stage III: Lesions have spread into the ligaments holding the uterus and around the rectum
  • Stage IV: The lesions extend until they involve the rectal wall, recto-sigmoid zone and the peritoneum, with the “Recto-Uterine Pouch” being filled with lesions

i Sanjay K. Agarwal, et al., Clinical diagnosis of endometriosis: a call to action, American Journal of Obstetrics and Gynecology, Volume 220, Issue 4, 2019, Pages 354.e1-354.e12, ISSN 0002-9378, https://doi.org/10.1016/j.ajog.2018.12.039.
ii By Endometriosis_loc_ger.svg: *Female_anatomy.svg: Tsaitgaist derivative work: H CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=9741343
iii Gordts S, Koninckx P, Brosens I. Pathogenesis of deep endometriosis. Fertil Steril. 2017 Dec;108(6):872-885.e1. doi: 10.1016/j.fertnstert.2017.08.036. Epub 2017 Oct 31. PMID: 29100623.