Endometriosis is a condition where cells that form the lining of the uterine cavity (endometrial cells) grow outside of the uterus, most commonly overlying pelvic organs. This condition is associated with infertility, though it has not been proven that endometriosis causes infertility.

Approximately 15-20% of women in the general population have endometriosis. Of women with the diagnosis of infertility, 25-35% are diagnosed with endometriosis. A grading system for severity of disease has been devised. Minimal disease implies a few pelvic endometriosis implants but normal anatomical relationship of the tubes and ovaries, while severe disease can include extensive adhesions surrounding the pelvic organs. Most women with endometriosis (about 60%) have minimal to mild disease. Symptoms of endometriosis are two-fold: pelvic pain and/or infertility. The grade of the disease does not correlate to the symptomatology; in other words a patient with minimal disease can have debilitating pelvic pain, while a patient with severe disease can be pain free but have infertility.

Endometriosis is diagnosed by performing surgery (laparoscopy). Most experienced laparoscopists will be able to identify endometriosis by characteristic features of the lesions, which can be found anywhere within the pelvis. The most common sites are behind or on the uterus, on the fallopian tubes or ovaries, over the bladder or bowel. The experienced surgeon will do a thorough survey of the pelvis at the time of surgery to look for characteristic lesions, and may also biopsy some lesions. There have been reports of endometriosis outside of the pelvic cavity, such as in surgical scars, around the lungs or heart, and even more rarely around the brain.

The mechanism by which one gets endometriosis is still unclear. The most popular theory was originally described by Sampson in the 1920s, suggesting that endometrial tissue is deposited in the pelvic cavity by the mechanism of retrograde menstrual flow through the fallopian tubes. There are numerous subsequent observations that support this original theory. In addition, more recent theories suggest that the presence of endometriosis lesions causes changes in the local pelvic environment, which now renders it unfavorable to the important and necessary steps required for pregnancy (early follicle development, fertilization and embryo development). As we gain more insight into the origin of the disease, we will have strategies for therapeutic interventions.

Medical intervention for endometriosis must specifically target the primary symptom, since oftentimes the treatment for one symptom may interfere with the overall desired result. For instance, if the primary goal is managing pelvic pain, medical management (birth control pills, progestins, GnRH agonists) can be quite effective, but will not improve or preserve fertility. Additionally, these medications will prevent pregnancy. Surgery can also improve pain symptoms, especially for patients with advanced disease. It the primary symptom is infertility, medical suppression would not play a role. Surgical management can improve fertility for patients with moderate to severe disease who have anatomical distortion of their pelvic organs due to adhesions, scarring or large endometriosis cysts of the ovaries. For patients with minimal to mild disease (no anatomical distortion of pelvic organs), it is controversial as to whether surgery will improve fertility chances. If so, surgery probably provides a minimal increase in fertility (from about 5% to 8% PR/month).

Most studies confirm that patients with even minimal to mild endometriosis have much lower pregnancy rates than women without this diagnosis. A hypothetical 32 year old patient with mild endometriosis would have about a 5% monthly pregnancy chance, compared to a 25% chance for her 32 year old friend with no infertility.

Treatment options depend on several factors such as the stage of the disease process (minimal vs. severe disease), the presence of scar tissue around pelvic organs, the age and FSH/Estradiol levels (indication of egg quality) of the patient. These options would include using fertility pills (Clomiphene Citrate), fertility shots (gonadotropins), or pursuing in vitro fertilization (IVF) treatment. Your physician can provide a recommendation as to which of these would be the best initial step, after a full evaluation has been conducted.

Controversies

Areas of current controversy concerning endometriosis and fertility treatment include:

Whether a laparoscopy should be performed for patients with unexplained infertility, to diagnose endometriosis
(Formerly laparoscopies were recommend for the evaluation of endometriosis prior to fertility treatment. Currently, if the patient is committed to treatment, and If there is no other reason for a laparoscopy, we will often simply proceed to treatment. )
Whether endometriosis ovarian cysts should be surgically removed prior to start of fertility treatment
(Formerly, surgery to remove endometriomas was recommended prior to treatment, especially IVF treatment. There are some recent studies suggesting that surgical intervention may actually damage eggs around the endometrioma, decreasing pregnancy rates. Currently, we may not recommend removing the endometrioma, unless it is above 6cm in size or provides symptoms.)
Whether all endometriosis lesions should be surgically removed, if the patient does not have symptoms of pelvic pain
(Current studies suggest that there may be some fertility improvement with trying to surgically remove all visible lesions, though the magnitude of improvement may not be large. The down side of an aggressive surgical approach is that more adhesions may form post surgery.)