Dr. Louis DePaolo, Chief of the Fertility and Infertility Branch at the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), spoke with NIH MedlinePlus magazine about developments in endometriosis research.
Why is it sometimes difficult to diagnose endometriosis?
Several of its symptoms, such as pain and infertility, mimic symptoms of other conditions. However, some women with endometriosis show no symptoms. Currently, the diagnosis is confirmed with surgery. Unfortunately, this procedure is expensive and may not be covered by all insurance plans.
What are the suspected causes of endometriosis? Who is at risk for this condition?
Multiple factors appear to cause endometriosis. For years, the theory was that tissue fragments “shed” from the lining of the uterus during menstruation and then were propelled backwards into a cavity of the abdomen. But we now know that this process, called “retrograde menstruation,” is a normal process experienced by many reproductive-age women. Newer theories speculate that some women may have an underlying condition—such as certain defects in the tissue of the endometrium or possibly inflammation—that leads to the development of the shed-tissue fragments.
It is estimated that six to 10 percent of women during reproductive age have endometriosis—about 5 million women in the U.S. In 2011, an NICHD study found that 11 percent of a group of women had the disorder, but presented no symptoms. This finding could mean that many more women have the disorder without realizing it.
Although all women of reproductive age are at risk for developing endometriosis, genetics and possibly exposure to toxins in the environment may be significant factors in the development of the disease.
How is research on the genetic components of endometriosis helping with diagnosis?
Over the past two decades, researchers have worked to discover whether certain genetic modifications may be involved in endometriosis by examining tissue from the endometrium in women with and without the disease. This work has led to the development of “genetic signatures” that may be useful in diagnosing endometriosis. Research also has helped identify certain proteins found in the blood that might serve as biomarkers, predicting the development of the disease. Ultimately, the goal is to develop noninvasive or minimally invasive approaches to diagnose endometriosis, instead of surgery.
Find Out More
- Eunice Kennedy Shriver
National Institute of Child Health and Human Development (NICHD):
- MedlinePlus: Endometriosis: medlineplus.gov/endometriosis.html
- National Center for Biotechnology Information (NCBI):
- Clinical Trials: Endometriosis:
- Endometriosis Foundation of America:
- Endometriosis Association:
What does research tell us about how endometriosis is involved with fertility in some women?
This is one of the most perplexing aspects of the disease, confronting researchers and patients alike: What is the relationship between endometriosis and infertility? An estimated 30 to 50 percent of infertile women may have endometriosis. Not only do some of these women have difficulty conceiving and carrying a live birth to term, they are less likely to conceive following assisted reproduction, such as fertility medication, artificial insemination, and in vitro fertilization. Studies to address the link between endometriosis and infertility have just begun. These studies suggest that women with endometriosis may have implantation defects (abnormalities of the environment that make it difficult for the embryo to attach and survive) and/or low quality eggs. These conditions, in turn, could be related to an abnormal immune environment that some suspect exist in women with endometriosis.
Many women with endometriosis have intense pelvic pain. What treatment options are available for endometriosis-related pain?
Most treatments for ending or reducing the pelvic pain involve hormonal treatments. These treatments interfere with the menstrual cycle and may interrupt or halt menstruation temporarily or permanently. Interestingly, the size of the endometriotic lesion does not correlate well with pain severity.
What's the future of endometriosis research?
Dr. DePaolo highlights these research efforts in endometriosis:
- Developing ways to diagnose the disease without surgery
- Identifying new treatments using randomized clinical trials with patients who have been screened for disease severity, pelvic pain, and infertility
- Continuing to mine and integrate various databases to help uncover novel theories of how lesions begin, develop, and progress
- Increasing the study of how epigenetic (changes to gene function not involving DNA) factors relate to the frequency of disease. These epigenetic factors may be influenced by environmental exposures that can be transmitted to future generations
- Investigating the stem cell origins of the disease
- Researching ways to better understand how endometriosis and infertility effect and relate to each other
- Continuing development of animal and in vitro models to study how the disease begins, progresses, and responds to new treatment