Endometriosis Risk Factors


Are you experiencing period cramps that become worse or pelvic pain that happens when you are not menstruating? While period cramps are a common complaint of people who menstruate, intense period cramps and abnormal pelvic pains are associated with endometriosis. 

Before you start worrying about your period cramps, you can check if you have the risk factors that indicate a higher risk for endometriosis. This article will briefly explain the genetic and environmental risk factors that increase one’s risk for endometriosis. 

What is endometriosis?

Endometriosis is a condition where endometrial tissues are present outside of the uterus at abnormal locations.1 The endometrial tissues make up the layer of the uterus lining (endometrium) that normally sheds every month during your period. Some common locations where this abnormal growth of tissue occurs are the ovaries, the Fallopian tube, and the inner lining of the abdomen and pelvis. This condition can also happen outside of the pelvic area, such as the gastrointestinal tract, soft tissue, and urinary tract.2 

Endometriosis is also described as a chronic inflammatory disease. After being implanted at abnormal locations outside of the uterus, the endometrial tissues develop as they would in the uterus but cannot be removed normally from the body when it breaks down. This can cause bleeding, inflammation, and the formation of scar tissues.7

According to the World Health Organisation, endometriosis affects about 10% of women at reproductive age around the world. 


Endometriosis can be very debilitating as it can cause 1) pelvic pain and 2) infertility in the people affected.3 These two symptoms are the most common symptoms of endometriosis.

The pelvic pain that people with endometriosis might experience can be cyclical, persistent, and progressively worsen.

There are also some other symptoms that you should look out for, including:4

  • Dysmenorrhea - period cramps
  • Dyspareunia - persistent pain in the genital area during, before, or after sexual intercourse
  • Dysuria - painful sensation when urinating
  • Dyschezia - feeling pain or having difficulty in pooping
  • Menorrhagia - heavy menstrual bleeding 

Risk factors

There are genetic factors and environmental factors that can put an individual at higher risk for endometriosis. Let us take a look at what these risk factors are.

Family history of endometriosis

Research has suggested that people affected by endometriosis tend to have family members who are also affected. In fact, people who have first-degree relatives with endometriosis may have a 6-9% likelihood of developing endometriosis.5 This is why some researchers propose that endometriosis can be passed down genetically. Some of the genes associated with the risk for endometriosis are involved in these functions:13

  • Immune and inflammatory functions
  • Tissue structure
  • Hormone functions
  • Development and proliferation of cells
  • Generation of blood vessels

Genetic factors can also interact with environmental factors to increase the risk for endometriosis.    

History of abdominal surgery

Although rare, abdominal surgery can increase the risk for scar endometriosis, which is a condition where endometrial cells grow in the surgical scar tissues. Scar endometriosis typically happens in people who have a Caesarean section. 2 theories were proposed to explain the occurrence of scar endometriosis:9

  1. Stem cells with the capability of becoming another cell type develop into endometrial tissues under suitable conditions. 
  2. Endometrial cells get transported and implanted into scarred areas. 

Exposure to oestrogen or inflammatory conditions helps promote the growth of endometrial cells in the abnormal sites that they get implanted into.8

Exposure to endocrine-disrupting chemicals

Endocrine-disrupting chemicals (EDCs) are chemicals that interfere with the endocrine system in regulating hormone actions. These EDCs either mimic or block the actions of hormones and lead to irregularities in normal biological processes. Some of these EDCs can also disrupt the actions of the immune system and encourage the development of endometriosis. EDCs have the potential to affect the development of the baby if a pregnant person is exposed to them. Here are some examples of EDCs that are linked to an increased risk for endometriosis:10, 11

  • Phthalates - present in plastics and cosmetic products
  • Bisphenol A (BPA) - present in plastics
  • 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD/dioxin) - produced as the byproduct of volcanic eruptions, paper mill, fossil fuel burning, and herbicide/pesticide production


There are studies that looked into the relationship between smoking and the risk of endometriosis. However, the results of these studies are inconsistent and conflicting. Some studies reported an increase in the risk for endometriosis among smokers, while some studies did not find this correlation or suggested the opposite.6 

Although there is no definite proof that shows smoking increases the risk for endometriosis, it is known that smoking can harm your reproductive system and cause lower fertility. Therefore, it is strongly encouraged to quit smoking. 

Abnormally long periods or short menstrual cycles

The most popular theory of how endometriosis happens is the retrograde menstruation phenomenon. This theory suggests that endometrial tissues might backflow through the fallopian tubes into the pelvic cavity during a period, which allows the implantation at an abnormal site.

Normally, a menstrual cycle should last for approximately 28 days, with a period lasting about 4-7 days. When the periods last for too long, the chances of retrograde menstruation happening may increase, therefore increasing the risk for endometriosis.3 

A study conducted in 2016 also suggested that a short menstrual cycle (<27 days) is associated with higher risks of endometriosis. The researchers explained that abnormally short menstrual cycles might mean that you get your period more frequently. This increases the chance for retrograde menstruation to take place. Oestrogen is the main sex hormone that stimulates the proliferation of endometrial cells in the uterus. Oestrogen levels peak before ovulation and drop sharply after ovulation, then followed by a second increase before the menstrual cycle ends. The researchers suggested that people with shorter menstrual cycle may also be exposed to high levels of oestrogen frequently, which promote the growth of endometrial tissues outside of the uterus.12


Endometriosis affects about 10% of women of reproductive age and can cause debilitating symptoms such as pelvic pain and infertility. Knowing the risk factors of endometriosis may help you identify your risks and seek early medical advice if you are at high risk. Family history, history of abdominal surgery, exposure to endocrine-disrupting chemicals, and abnormally long periods or a short menstrual cycle are possible risk factors for endometriosis that you should take note of. Whether smoking increases the risk of endometriosis is unclear, but smoking can cause lower fertility and damage the reproductive system. Therefore, it is still strongly encouraged to stop smoking.


  1. Mehedintu C, Plotogea M, Ionescu S, Antonovici M. Endometriosis still a challenge. J Med Life [Internet]. 2014 Sep 15 [cited 2022 Oct 19];7(3):349–57. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4233437/ 
  2. Lee HJ, Park YM, Jee BC, Kim YB, Suh CS. Various anatomic locations of surgically proven endometriosis: A single-center experience. Obstet Gynecol Sci [Internet]. 2015 Jan [cited 2022 Oct 19];58(1):53–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4303753/ 
  3. Missmer SA. Incidence of laparoscopically confirmed endometriosis by demographic, anthropometric, and lifestyle factors. American Journal of Epidemiology [Internet]. 2004 Oct 15 [cited 2022 Oct 22];160(8):784–96. Available from: https://academic.oup.com/aje/article-lookup/doi/10.1093/aje/kwh275 
  4. Vercellini P, Viganò P, Somigliana E, Fedele L. Endometriosis: pathogenesis and treatment. Nat Rev Endocrinol [Internet]. 2014 May [cited 2022 Oct 19];10(5):261–75. Available from: https://www.nature.com/articles/nrendo.2013.255 
  5. Agarwal SK, Chapron C, Giudice LC, Laufer MR, Leyland N, Missmer SA, et al. Clinical diagnosis of endometriosis: a call to action. American Journal of Obstetrics and Gynecology [Internet]. 2019 Apr 1 [cited 2022 Oct 19];220(4):354.e1-354.e12. Available from: https://www.sciencedirect.com/science/article/pii/S000293781930002X 
  6. Koninckx PR, Ussia A, Adamyan L, Wattiez A, Gomel V, Martin DC. Pathogenesis of endometriosis: the genetic/epigenetic theory. Fertility and Sterility [Internet]. 2019 Feb 1 [cited 2022 Oct 21];111(2):327–40. Available from: https://www.sciencedirect.com/science/article/pii/S0015028218321356 
  7. Vassilopoulou L, Matalliotakis M, Zervou MI, Matalliotaki C, Krithinakis K, Matalliotakis I, et al. Defining the genetic profile of endometriosis. Exp Ther Med [Internet]. 2019 May [cited 2022 Oct 24];17(5):3267–81. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6447774/ 
  8. Akbulut S, Mahsuni Sevinc M, Bakir S, Cakabay B, Sezgin A. Scar endometriosis in the abdominal wall: a predictable condition for experienced surgeons. Acta Chirurgica Belgica [Internet]. 2010 Jan 1 [cited 2022 Oct 23];110(3):303–7. Available from: https://doi.org/10.1080/00015458.2010.11680621 
  9. Carsote M, Terzea DC, Valea A, Gheorghisan-Galateanu AA. Abdominal wall endometriosis (A narrative review). Int J Med Sci [Internet]. 2020 Feb 10 [cited 2022 Oct 23];17(4):536–42. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7053307/ 
  10. Rumph JT, Stephens VR, Archibong AE, Osteen KG, Bruner-Tran KL. Environmental endocrine disruptors and endometriosis. Adv Anat Embryol Cell Biol [Internet]. 2020 [cited 2022 Oct 23];232:57–78. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7978485/ 
  11. Tanha M, Bozorgmehr M, Shokri MR, Edalatkhah H, Tanha M, Zarnani AH, et al. 2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin potential impacts on peripheral blood mononuclear cells of endometriosis women. Journal of Reproductive Immunology [Internet]. 2022 Feb 1 [cited 2022 Oct 24];149:103439. Available from: https://www.sciencedirect.com/science/article/pii/S0165037821001698 
  12. Bravi F, Parazzini F, Cipriani S, Chiaffarino F, Ricci E, Chiantera V, et al. Tobacco smoking and risk of endometriosis: a systematic review and meta-analysis. BMJ Open [Internet]. 2014 Dec 22 [cited 2022 Oct 21];4(12):e006325. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4275697/ 
  13. Wei M, Cheng Y, Bu H, Zhao Y, Zhao W. Length of menstrual cycle and risk of endometriosis. Medicine (Baltimore) [Internet]. 2016 Mar 7 [cited 2022 Oct 24];95(9):e2922. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4782879/ 

Pei Yin Chai

Bachelor of Science - BS, BSc(Hons) Neuroscience, The University of Manchester, England

Pei Yin (Joyce) is a recent neuroscience degree graduate from the University of Manchester. As an introvert, she often finds it easier to express herself in written words than in speech, that's when she began to have an interest in writing. She has 2 years of experience in content-creating, and has produced content ranging from scientific articles to educational comic and animation. She is currently working towards getting a career in medical writing or project management in the science communication field.

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