A problem common in women, endometriosis affects an estimated 5 million in the United States alone. The condition affects a woman’s uterus—the place where a baby grows during pregnancy.
The tissue that normally lines the inside of the uterus grows outside the uterus, causing pain, infertility, and very heavy periods. While the pain is usually in the abdomen, lower back, or pelvic areas, some women have no symptoms. For them, having trouble getting pregnant may be the first sign.
The cause of endometriosis is not known. Pain medicines and hormones often help. Severe cases may need surgery. There are also treatments to improve fertility in women with endometriosis.Researchers used to think that patches growing outside the uterus caused the pain. In fact, the size and location of these patches are not related to the severity of pain or to the location of the pain.
What causes endometriosis?
The exact cause of endometriosis is not known, but researchers have some theories:
- Genes are most likely involved to some degree, because the condition runs in families,
- Estrogen (a hormone involved in the female reproductive cycle) also likely contributes to it, because it is an estrogen-dependent, inflammatory disease.
- Progesterone resistance may be the cause. This is where the mucus membrane lining the uterus doesn't respond as it should to progesterone, another hormone involved in the female reproductive cycle.
- Immune system dysfunction plays a role in some cases, where the immune system fails to destroy endometrial tissue, which enables it to grow outside the uterus.
- Environmental exposures in the womb, such as to chemicals like dioxin, may also cause the condition.
What are the risk factors of endometriosis?
Studies show that women are at higher risk for endometriosis if their:
- Mother, sister, or daughter had endometriosis (raises the risk about six times)
- Periods started at an early age (before age 11)
- Monthly cycles are short (less than 27 days)
- Menstrual cycles are heavy and last more than 7 days
What are the symptoms of endometriosis?
While the primary symptoms of endometriosis are pain and infertility, other common symptoms include:
- Painful, even debilitating, menstrual cramps, which may get worse over time
- Pain during or after sex
- Pain in the intestine or lower abdomen
- Painful bowel movements or painful urination during menstrual periods
- Heavy menstrual periods
- Premenstrual spotting or bleeding between periods
What are the treatments for endometriosis?
Treatments for endometriosis pain fall into three general categories:
- Pain medications
- Hormone therapy
- Surgical treatment
Research shows that some surgical treatments can provide significant, although short-term, pain relief from endometriosis.
Treatments for infertility related to the condition include in vitro fertilization (IVF), which makes it possible to combine sperm and eggs in a laboratory to make an embryo. The resulting embryos are placed into the woman's uterus.
Not all treatments work well for all women with the condition. Similarly, there is always the chance that the symptoms may return after the treatment is stopped.
For more information on treatment options, visit:
NIH's endometriosis treatment page.