What is endometriosis?
Endometriosis is the name give to a disease in which the tissue which normally grows in the uterus (endometrium) grows outside of the uterus. It is commonly associated with pelvic pain and infertility. The most common symptoms of endometriosis are pain with periods, pelvic pain at times other than during the period, pain with intercourse, bowel symptoms (diarrhea, cramping, constipation, pain with defecation), urinary symptoms (painful bladder, pain with urination) and infertility.
How common is endometriosis?
Endometriosis has been found in about 6-10% of reproductive aged women. In women with fertility problems it is much more common (21-47% of women). Those women with chronic pelvic pain have the highest prevalence (71-87%). The average age at the time of diagnosis is 28 years old.
Is endometriosis a genetic disease?
Endometriosis is a complex disease that has a definite genetic component. First of all, it does run in families. If a sister or mother has endometriosis, the risk for a woman to have endometriosis is 7-10 times higher. Genetic studies have (so far) identified seven genetic areas that increase the risk of endometriosis. The more abnormal genetic areas a woman has, the more severe the degree of endometriosis.
How does endometriosis cause infertility?
The more severe forms of endometriosis is associated with scar tissue in the abdomen which causes distortion of the pelvic anatomy which makes it harder for an egg to get into the fallopian tube at the time of ovulation. It is uncertain about how milder endometriosis may cause infertility.
One theory suggests that a woman’s eggs might be directly affected. For example, a study looking at the use of donated eggs found no difference in pregnancy rates between women with endometriosis and those without. This would suggest an egg problem. However, another study looked at the practice of splitting the eggs from one egg donor into two women (one with and one without endometriosis) and found lower pregnancy rates in the endometriosis group. This would suggest a uterine problem.
How is endometriosis diagnosed?
The gold standard for diagnosing endometriosis is still surgery with biopsy of suspected areas and subsequent confirmation under the microscope. Much effort has gone into trying to find a blood test that could accurately identify endometriosis but to date such a marker remains elusive.
How is endometriosis treated?
First, the goals of treatment must be determined. At the present time, there is no “cure” for endometriosis.
Treatment to control pain
Treatment to alleviate pain is different than treatment to improve fertility. For the control of pain, the main objective is the suppression of hormones that cause endometriosis to develop. A number of medications can accomplish this.
The medications in birth control pills (synthetic estrogen and progesterone) have been shown to work better than a placebo. This is true when combined or even when synthetic progesterone is used alone. The most well studied synthetic progesterone is called norethindrone.
Gonadotropin releasing hormone agonists (GnRHa) such as Lupron have also been shown to work better than placebo and are as effective as synthetic progesterone. However, this therapy is associated with short term side effects which result from the lowering of estrogen levels (hot flashes, vaginal dryness etc) and long term reductions in estrogen will decrease bone density and raise the risk for fractures. As a result, GnRHa are limited to 6 months of use. However, combining GnRHa with other medications may allow longer term use.
Surgery can also be used to control pain symptoms. Studies show that laparoscopy to eradicate endometriosis decreased pain better than a “diagnostic” only surgery. There is a problem with pain recurrence, however. Many studies have found that the recurrence risk can be reduced by using medical suppression after surgery.
Treatment to improve fertility
For the improvement of fertility, studies have found that surgery for milder stages of endometriosis has a beneficial effect. However, the impact is relatively small. You would have to do surgery and eradicate endometriosis on 11 patients in order to get one extra pregnancy. For more severe stages of endometriosis, there is more uncertainty about whether surgery helps. And there is some risk. Women with endometriosis involving the ovaries are more likely to have decreased ovarian reserve. Surgery to remove ovarian endometriosis will further decrease this reserve.
IVF does improve the chance for pregnancy in women with endometriosis. It is unclear whether endometriosis still has some impact, however. One study, looking at the U.S. IVF registry (SART) found that women with endometriosis only (no other infertility diagnoses) had a similar to slightly higher pregnancy rate in IVF compared to other diagnoses.
Medical suppression of endometriosis such as described above for pain, do not increase fertility and, in fact, results in less pregnancies per time because pregnancy cannot be attempted during the time of suppression. It is unclear whether suppression with GnRHa for 2-6 months prior to IVF will improve the chances for IVF to produce pregnancy.