Endometriosis: Why does my period hurt?

What is endometriosis?

Endometriosis is when tissue that is similar to the lining of the uterus, grows outside of the uterus, creating lesions that can cause extreme pain and/or infertility. This lining layer that grows inside the uterus is called the endometrium. This is the layer that builds and sheds each month with menstruation and also where a pregnancy will attach and grow.

These endometrial like lesions are most commonly found in the abdomen or pelvis, on structures like the bowel, bladder and ovaries, but they can also be found in other places such as the lungs, nasal cavity and lower limbs! These lesions can grow and become painful and inflamed, contributing to scar tissue and adhesions (1, 2).


Symptoms of Endometriosis:

Endometriosis has a few key characteristics. One of them is experiencing significant amounts of pain that can, but doesn’t always correlate with your period. People with "endo" may have any of the following:

  • Pain on or around ovulation (Mittelschmerz)
  • Pan on or around the time of your period (dysmenorrhea)
  • Pain during or after sex (dyspareunia)
  • Pain with bowel movements (dyschezia)
  • Pain when you urinate (dysuria)
  • Pain in your pelvic region, lower back, and legs
  • Having trouble holding on when you have a full bladder or having to go frequently
  • Heavy or irregular bleeding
  • Digestion issues
  • Bleeding between periods
  • Fatigue


What causes endometriosis?

The cause of endometriosis is believed to be multifactorial and it’s likely that hormonal factors, inflammatory factors, genetic factors, and immunologic factors all play their own role in this condition.


How do you diagnose endometriosis?

Getting an accurate diagnosis of endometriosis takes on average 6.5 years in Australia and can be a frustrating process for many. The gold standard and only way to accurately diagnose endometriosis is by having a laparoscopy and biopsy taken by a skilled laparoscopic surgeon. This is keyhole surgery performed under a general anaesthetic and allows the surgeon to see inside your pelvic cavity. It is not uncommon for a doctor to suggest a “clinic diagnosis” of endometriosis, based on your symptoms, clinical presentation and exclusion of other causes, without having done a laparoscopy. However remember that the only way to truly diagnose this condition is via laparoscopy. Surgeons will often also perform an excision during a diagnostic laparoscopy of any endometriosis found, which can be an effective treatment technique for many.


How is endometriosis staged?

Not all endometriosis is the same and every case is unique in its presentation. It’s also important to remember that your level of pain and symptoms might not correlate with your stage. It’s not uncommon for individuals with stage 1 endo to have debilitating symptoms, while some with stage 3 may have more mild symptoms.

When a laparoscopic surgery is performed, endometriosis can be classified into one of four categories: minimal (stage 1), mild (stage 2), moderate (stage 3), severe (stage 4). The most used and best-known system was developed by the American Society for Reproductive Medicine (ASRM – formerly ASF). Symptoms and pain may not relate to the stage you have, so that’s also important to know.


Endometriosis Stage

How it appears

Stage 1 (1-5 points)


Few superficial lesions

Stage 2 (6-15 points)


More and deeper lesions

Stage 3 (16-40 points)


Many deep lesions

Small cysts on one or both ovaries

Presence of adhesions

Stage 4 (>40 points)


Many deep implants

Large cysts on one or both ovaries

Many dense lesions


So what are my treatment options? Read about how endometriosis may be treated here


These resources may be helpful to you if you currently suffer with endometriosis:



  1. Parasar P, Ozcan P, Terry KL. Endometriosis: epidemiology, diagnosis and clinical management. Current obstetrics and gynecology reports. 2017;6(1):34-41.
  2. Nisolle M, Donnez J. Peritoneal endometriosis, ovarian endometriosis, and adenomyotic nodules of the rectovaginal septum are three different entities. Fertility and sterility. 1997;68(4):585-96.
  3. Meresman GF, Augé L, Barañao RI, Lombardi E, Tesone M, Sueldo C. Oral contraceptives suppress cell proliferation and enhance apoptosis of eutopic endometrial tissue from patients with endometriosis. Fertility and sterility. 2002;77(6):1141-7.
  4. Vercellini P, Frontino G, De Giorgi O, Aimi G, Zaina B, Crosignani PG. Comparison of a levonorgestrel-releasing intrauterine device versus expectant management after conservative surgery for symptomatic endometriosis: a pilot study. Fertility and sterility. 2003;80(2):305-9.