Spotlight: What to Know About Endometriosis

Monday, March 12, 2018
Cells of the endometrium dyed different shades of pink and purple.
Microscopy view of endometrium.
--Stock Image

Endometriosis is a condition in which tissue similar to the endometrium—the lining of the uterus—grows outside the uterus. The most common symptoms of endometriosis are pain and infertility. Health care providers don't know what causes endometriosis, but there are some effective treatments available.

Understanding endometriosis—its causes, mechanisms, and treatments—is central to the scientific mission of NICHD's Gynecologic Health and Disease Branch. We asked Lisa Halvorson, M.D., chief of the branch, to share some of her thoughts on endometriosis and the research supported by her branch.

Q. How common is endometriosis?

A. Current estimates suggest that approximately 10% of reproductive-age women have endometriosis. However, a substantial number of women go undiagnosed, so this is likely an underestimate.

Q. What do you think is the least known aspect of endometriosis?

A. At the most basic level, the least known aspect of endometriosis is that so few people even know it exists as a disorder. Women and physicians don't always realize the various symptoms and ways it can appear. These can include not only infertility, but subfertility (taking a longer time to get pregnant), pelvic pain associated with the menstrual cycle, chronic pelvic pain, pain during sex, pain during urination, pain with defecation (bowel movements), and pain in the lower back or thighs. Sometimes the pain is intense or debilitating. But sometimes, there is no pain, which of course makes it harder to detect.

Q. What would your advice be to a woman who thinks she might have endometriosis, but is embarrassed to ask her health care provider about it?

A. At this time, only a health care provider can diagnose endometriosis. Therefore, it's important for patients to share with their doctor any pain or discomfort without feeling embarrassed. Pain is not normal. Remember, a health care provider, by definition, wants to care for your health, but needs your information to offer the right care. Getting treatment is important because endometriosis, if left untreated, can cause scarring and damage to pelvic organs (ovaries and Fallopian tubes). So even if a woman is embarrassed, it's important that she find a way to talk with her health care provider. Some women feel more comfortable talking to a close friend or family member who perhaps could accompany the woman to speak with the provider. Several organizations also offer guides on how to talk with your health care provider about topics that might be embarrassing; these might also help.

Q. Your branch focuses on gynecologic health—how does the branch plan to advance knowledge and understanding about endometriosis?

A. The Gynecologic Health and Disease Branch supports a broad range of research to advance our knowledge of endometriosis, from work in the lab to research studies with women. Some work focuses on understanding how common endometriosis is in different populations and ethnic groups. Other studies address the cause or causes of endometriosis, such as genetics, because we do see an increased frequency of the disorder within some families. We also examine the impact of diet or exposure to environmental toxins within the context of causing or contributing to endometriosis. We are also exploring new diagnostics and, importantly, new treatments. In terms of promoting awareness, we collaborate with different organizations to develop educational tools for women, encouraging them to seek a medical diagnosis. Finally, we participate and sometimes host conferences and roundtables—these may focus on new directions in endometriosis research or on educating health care providers about signs and symptoms to look for in patients.

Q. What do you think is the most promising avenue of research related to endometriosis?

A. We're excited about two highly promising areas of research:

  • Development of novel therapies for endometriosis symptoms
  • Non-invasive or minimally invasive ways to diagnose endometriosis

Within the novel therapies arena, one recent clinical trial  included more than 800 women who had been diagnosed with endometriosis. They received an oral medication called elagolix over a 6-month period. This drug is specifically designed to treat endometriosis pain. The trial showed that women who received the medication had reduced pelvic pain.

Currently, the only way to diagnose endometriosis is by surgery. Providers can make a probable diagnosis using ultrasound in those patients with an endometriosis cyst on their ovary (endometrioma); however, this is uncommon in most patients. Finding reliable non-surgical ways to diagnose the condition will help women get answers faster, so they can be treated sooner, maybe before permanent damage is done to pelvic organs. Pain is not normal, and living with chronic, sometimes intense pain takes a toll. Several researchers and biotech companies are developing promising markers that might detect endometriosis in saliva, blood, or menstrual tissue.

Other work includes screening uterine tissue to detect gene activity patterns as a way to diagnose the presence and severity of endometriosis.

The overarching mission of the Gynecologic Health and Disease Branch is to improve women's health by guiding and supporting gynecologic research and career development programs. In 2016, the branch held a Scientific Vision meeting in which experts in the field discussed areas for future research in gynecologic field. These discussions contributed to the development of new research initiatives and high program priorities aimed at accelerating our understanding of gynecologic disorders. The diagnosis and management of endometriosis was one of four major areas of consideration and remains a key focus of our efforts. Details on the outcome of this meeting will soon be available on the NICHD website. Together, the branch and the members of the gynecologic research community are working toward a future in which women lead lives free from the effects of gynecologic disorders.

Recent NICHD-Funded Findings on Endometriosis

Risk Factors/Environment

Fruit and vegetable consumption and risk of endometriosis.
Researchers found that a higher intake of fruits, particularly citrus fruits is associated with a lower risk of endometriosis

History of breast feeding and risk of incident endometriosis: prospective cohort study.
Exclusive breastfeeding was significantly associated with a lower risk of endometriosis.

Associations among body size across the life course, adult height and endometriosis.
Both body size and height are associated with endometriosis risk. Few studies have looked at how a woman's body weight and height might relate to endometriosis across the lifespan.

Endometriosis and Ovarian Cancer

Endometriosis and risk of ovarian and endometrial cancers in a large prospective cohort of U.S. nurses.
This study adds to previous evidence that endometriosis is not strongly linked to endometrial cancer risk.

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