NICHD conducts and supports a range of research activities to learn more about causes, risk factors, and treatments for endometriosis. Short descriptions of this research follow below.
Extramural Research on Endometriosis
The Institute supports research on endometriosis mostly through its Fertility and Infertility (FI) Branch and Gynecologic Health and Disease Branch, but also through other extramural organizational units. Findings from recent research efforts include (but are not limited to) the following:
- Researchers discovered the source of a cell type that is central to endometriosis, endometrial stromal fibroblasts (eSF). In endometriosis, eSF are unable to respond to progesterone and do not function properly, producing inflammation and pain. The research helps explain how eSF develop and how they become prone to inflammation. See NIH-Funded Study Uses Lab Cultures to Trace Problem Cells Back to Their Source for more information.
- NICHD and the National Cancer Institute funded a study that found that women with endometriosis had an increased risk of heart disease. Women who had a hysterectomy and had their ovaries removed were at even higher risk. See Endometriosis Linked to Increased Risk for Heart Disease for more information.
- Genetic inheritance is a known risk factor for endometriosis. Because microRNAs (miRNAs) are important regulators of gene expression, FI Branch-supported investigators focused on small changes in the DNA binding sites of 22 miRNAs previously linked to endometriosis. Visit Genetic Sequences Provide Clues to Endometriosis Risk for more details on this finding.
- An FI Branch–funded study was able to identify women who had endometriosis by analyzing genetic data obtained from uterine tissue. Visit High-Tech Analysis of Genetic Data May Yield New Test for Endometriosis to learn more about this work.
- Researchers funded by the FI Branch found that baboons with endometriosis treated with letrozole had much smaller patches of endometriosis after treatment. By contrast, the patches of endometriosis in the placebo-treated baboons had grown. (Source: Langoi, D. (2013). Fertility and Sterility, 99(3), 656–662.e3. PMID: 23257603)
- Researchers funded by the FI Branch found that selective inhibition of prostaglandin E (PGE) receptors decreases survival and invasion of human endometriotic cells. Selective inhibitors of PGE receptors might form the basis of potential nonsteroidal therapeutic options to treat endometriosis. (Sources: Lebovic, D. I., et al. (2013). Endocrinology, 154(12), 4803–4813. PMID: 24064359; Lee, J., et al. (2013). Biology of Reproduction, 88(3), 77. PMID: 23242524)
Intramural Research on Endometriosis
Division of Intramural Population Health Research (DIPHR)
DIPHR researchers study many different aspects of endometriosis. Among these efforts are the following:
- The Office of the Director is conducting the Endometriosis Natural History, Diagnosis, and Outcomes (ENDO) Study. This study is examining the health of women from geographic areas with known environmental contamination who were undergoing laparoscopy to assess the relation between exposure to persistent environmental chemicals and the incidence and severity of endometriosis.
- Findings from the study suggest that current statistics may greatly underestimate the number of women who have endometriosis. Among women seeking clinical care for endometriosis and a matched population cohort, endometriosis incidence ranged by two orders of magnitude by diagnostic method: 0.7% for histology only, 7% for MRI only, and 41% for visualized disease. The incidence of MRI-diagnosed endometriosis was 11% in the population cohort. Conservatively, then, 11% of women have undiagnosed endometriosis at the population level. These findings have implications for the design and interpretation of etiologic research, but also for the economic and overall health of the nation. (Source: Buck Louis, G. M., et al. (2011). Fertility and Sterility, 96, 360–365. PMID: 21719000)
- Among women participating in the ENDO Study, approximately 50% of women with endometriosis reported cyclic pelvic pain and 44% reported chronic pain, in comparison to 33% and 30% of women without gynecologic disorders, respectively. (Source: Schliep, K. C., et al. (2015). Human Reproduction, 30(10), 2427–2438. PMID: 27334336)
- In the first paper to look at women's fecundity before diagnosis of endometriosis, ENDO Study investigators found that women diagnosed with incident endometriosis were more likely than those without endometriosis to report taking longer to become pregnant. These findings need to be considered when evaluating fertility following diagnosis or treatment for a more complete understanding of fecundity and fertility among women with endometriosis. (Source: Buck Louis, G. M., et al. (2016). Journal of Women's Health, 25(10), 1021–1029. PMID: 27379997)
- One ENDO study detected specific proteins and environmental chemicals implicated in the development of endometriosis. See "Linking Endometriosis and Endocrine-Disrupting Chemicals" for more details.
- DIPHR researchers are also studying the origins of endometriosis, including intrauterine exposures. Visit Endometriosis Risk Might Begin Early for more information on this research.
Division of Intramural Research (DIR)
Currently, several Program in Reproductive and Adult Endocrinology (PRAE) components within the DIR are studying different features of endometriosis and its treatment. Some of these efforts include the following:
- PRAE researchers are also working to treat the symptoms of endometriosis more effectively. In one study, researchers examined women with chronic pelvic pain and endometriosis. They found that lesion depth, disease severity (burden), and the number of lesions were not associated with pain location. Only painful urination (dysuria) and midline abdominal pain were associated with location of superficial endometriosis lesions. (Source: Hsu, A. L., et al. (2011). Obstetrics and Gynecology, 118(2 Pt 1), 223–230. PMID: 21775836)
- PRAE-funded researchers compared U.S. and Puerto Rican women with endometriosis and found that both groups reported high rates of pain and infertility, but that the U.S. women reported even more pain and infertility than the Puerto Rican women. While endometriosis is universally characterized by pain and infertility, the differences between cultures could be related to genetics, access to care, cultural issues, and years dealing with the symptoms. (Source: Fourquet, J., et al. (2015). Journal of Endometriosis and Pelvic Pain Disorders, 7(4), 129–135. PMID: 27331050)
- In 2013, the World Endometriosis Society Montpellier Consortium published the first-ever worldwide consensus statement on the management of endometriosis. The statement, published in the journal Human Reproduction, addresses 69 issues related to the management of endometriosis. NICHD scientists and grantees were among those on the Consortium. Visit Global Consortium Identifies Best Management of Endometriosis for more information.
- The National Centers for Translational Research in Reproduction and Infertility (NCTRI) (Formerly the Specialized Cooperative Centers Program in Reproduction and Infertility Research [SCCPIR]) is a national network of research-based centers, supported by the FI Branch, that aims to promote interactions between basic and clinical scientists with the goal of improving reproductive health.
- Through the NCTRI, NICHD also supports Endometrium Database Resource housed at Baylor College of Medicine. Its purpose is to curate genes reported in the literature to be regulated in the uterus in human, mouse, rat, cow, guinea pig, pig, and sheep. The Resource supplies tools that allow easy comparison of relative RNA expression from different experimental conditions in curated publications to determine how those conditions affect gene expression in various layers of the uterus.
- The FI Branch-supported Reproductive Medicine Network (RMN) studies issues related to infertility and reproductive health in women. Several RMN studies are examining the effectiveness of assisted reproductive technology, such as IVF, in promoting pregnancy among women who are infertile, including those who have endometriosis-related infertility. The RMN is also performing a study to identify a non-invasive marker (ENDOmarker Study) and to validate the genetic signature in the endometrial biopsy found in women with endometriosis. The goal is to find a non-surgical way to diagnose endometriosis.