Endometriosis Risk Factors: An Overview
By Halle Tecco, MBA, MPH
Affecting an estimated 1 in 10 women during their reproductive years, endometriosis is when tissue that normally lines the uterus grows outside of the uterus, causing intense pain and fertility issues.  There’s a lot we don’t know about endometriosis, but we have established some risk factors, as well as some proactive factors, that can influence the likelihood of developing the condition.
What Is a Risk Factor?
A risk factor is essentially a characteristic, condition, or behavior that increases the likelihood of illness, injury, or harm.  In epidemiology, these are variables that have been statistically shown to be associated with a higher chance of a specific outcome. For instance, smoking is a risk factor for lung cancer. 
Just because a risk factor exists does not mean it will inevitably lead to the disease in question. A woman with a family history of breast cancer, for instance, has a higher risk but is not guaranteed to develop the disease. Risk factors serve more as warning signs, guiding both healthcare providers and patients in disease prevention and management strategies. 
Protective factors, on the other hand, are conditions or attributes—either individual or environmental—that decrease the likelihood of developing a disease or injury.  For instance, a balanced diet rich in fruits and vegetables is a protective factor against a host of diseases, including certain types of cancer. 
Just like risk factors, protective factors do not guarantee a certain outcome but significantly tilt the odds in favor of a more favorable result. They can be natural attributes, such as genetic makeup, or lifestyle choices, like abstaining from smoking. The understanding and promotion of protective factors are fundamental in preventive medicine.
Risk Factors for Endometriosis
Studies have shown that there are a number of risk factors associated with endometriosis, including:
Having a Relative With Endometriosis
Studies indicate that having a mother or sister with the condition increases one's risk.  This points to a genetic underpinning, although the exact genes involved are still under investigation. What is clear is that the disease often runs in families, making one's family medical history an important consideration when evaluating risk.
Early Age of First Period
The timing of your first menstrual cycle, known as menarche, has been linked to a small increased risk of developing endometriosis later in life.  Research has shown that those who experience their first period before the age of 11 are at a higher risk. The possible biological mechanisms behind this correlation are complex and not yet fully understood, but it might relate to the total lifetime exposure to estrogen, a hormone that plays a role in endometrial growth. [5-6]
Having Short or Heavy Menstrual Periods
The nature of your menstrual cycle is also a risk factor. Women with shorter monthly cycles (less than 27 days) or heavier menstrual periods that last more than 7 days have been found to be at a higher risk. [5-7] Shop the Cycle Support Bundle!
Infertility is a secondary condition that can develop from endometriosis.  The relationship between the two is akin to a feedback loop: endometriosis can lead to infertility, and being infertile may also point to a higher likelihood of having the condition. [5,6,8] Learn about getting pregnant with endometriosis →
Protective Factors for Endometriosis
There are also some factors that may lower the risk of endometriosis, including:
Pregnancy has been associated with a lower risk of developing endometriosis, likely because it temporarily halts menstrual cycles and lowers estrogen levels. [5,8,9]
Delayed Period Onset
Similar to how having a period that started early— before 11— puts you at higher risk for endometriosis, starting one's period later in adolescence may also offer some protective effects, although the reasons for this are not yet fully understood. 
Breastfeeding is another condition that has been linked to a lower risk of endometriosis.  The hormonal changes and absence of menstrual periods during breastfeeding might offer a protective period against the onset or progression of the disease. 
High Intake of Fruit
Dietary factors may also play a role. Consumption of more fruit, particularly citrus fruits, has been associated with a lower risk for endometriosis. 
How to Prevent Endometriosis
While you can't prevent endometriosis, you can reduce your chances of developing it by lowering any abnormally high levels of the hormone estrogen in your body.  That’s because the hormone plays a significant role in thickening the uterine lining during the menstrual cycle, which is pivotal in endometriosis pathogenesis.  Read my article on estrogen dominance for more information. Let’s discuss some endometriosis prevention methods, shared by The U.S. Department of Health and Human Services :
Hormonal Birth Control
Consult with your healthcare provider about hormonal birth control methods, such as pills, patches, or rings that contain lower doses of estrogen. Hormonal contraception is a common treatment for menstrual disorders and has been studied for its potential to reduce the risk of endometriosis.  In some cases, hormonal contraceptives can also be used to prevent a period from occuring altogether, also known as amenorrhea. Failing to menstruate at all can significantly improve or prevent endometriosis symptoms.
Engaging in regular exercise, particularly more than 4 hours a week, not only contributes to general health but also helps maintain a low percentage of body fat. A lean body mass is associated with decreased levels of circulating estrogen. 
Limit Alcohol Consumption
Large amounts of alcohol can raise estrogen levels. If you choose to consume alcohol, aim for no more than one drink per day. 
Cut Back on Caffeine
The research also suggests that more than one caffeinated drink per day, especially sodas and green tea, may increase estrogen levels. 
While you can't prevent endometriosis outright, these strategies focused on regulating estrogen levels can offer a semblance of control in a condition often characterized by its unpredictability. It's always best to discuss any lifestyle changes or medical treatments with a healthcare provider for personalized advice.
There is no infallible roadmap for avoiding endometriosis. Risk factors can inform you and your healthcare provider about potential vulnerabilities, thereby aiding in early diagnosis and intervention. Just remember that risk factors do not guarantee you have or will develop endometriosis. One thing that really stands out is the role of estrogen. Attempting to regulate this hormone, be it through medication (birth control) or lifestyle alterations, is perhaps the closest we can get to wielding some measure of control over endometriosis.
In the end, grappling with the risk and protective factors for endometriosis is less about seeking absolutes and more about knowing your personal risks. And in the realm of medical challenges like endometriosis, being better informed is itself a form of empowerment. Keep learning on the Natalist blog, or shop fertility and pregnancy products here.
- Self-Care for Endometriosis: Tips for Relief
- Endometritis vs. Endometriosis: What Is The Difference?
- Is Endometriosis an Autoimmune Disease?
- Endometriosis. World Health Organization. Accessed October 2023. URL.
- Resilient Wisconsin: Risk and Protective Factors. Wisconsin Department of Health Services. May 18 2023. https://www.dhs.wisconsin.gov/resilient/risk-protective-factors.htm
- What Are the Risk Factors for Lung Cancer? Division of Cancer Prevention and Control, Centers for Disease Control and Prevention. Accessed October 2023. URL.
- Healthy diet. World Health Organization. Accessed October 2023. URL.
- What are the risk factors for endometriosis? NIH. Accessed October 2023. URL.
- Nnoaham KE, Webster P, Kumbang J, Kennedy SH, Zondervan KT. Is early age at menarche a risk factor for endometriosis? A systematic review and meta-analysis of case-control studies. Fertil Steril. 2012;98(3):702-712.e6. doi:10.1016/j.fertnstert.2012.05.035
- Endometriosis. Office of Women’s Health. U.S. Department of Health & Human Services. Accessed October 2023. URL.
- Bulletti C, Coccia ME, Battistoni S, Borini A. Endometriosis and infertility. J Assist Reprod Genet. 2010;27(8):441-447. doi:10.1007/s10815-010-9436-1
- Peterson CM, Johnstone EB, Hammoud AO, et al. Risk factors associated with endometriosis: importance of study population for characterizing disease in the ENDO Study. Am J Obstet Gynecol. 2013;208(6):451.e1-451.e4511. doi:10.1016/j.ajog.2013.02.040