Endometriosis was described in medical literature more than 300 years ago and has been recognized since ancient times as a chronic, painful, and often progressive disease in women.
Endometriosis develops when fragments of endometrial (uterine lining) tissue become implanted outside the uterine cavity, usually in other areas of the pelvis. This results in normal tissue growing in an abnormal location. The implants consist of both endometrial gland cells (which secrete hormones and other fluids) and stroma cells (which build supportive tissue). These cells contain receptors that bind to estrogen and progesterone, which are responsible for uterine growth and thickening.
Each month, these exiled endometrial implants respond to the monthly cycle, just as they would in the uterus, filling with blood, thickening, breaking down, and bleeding. The products of the process, however, cannot be shed through the vagina during menstruation. Instead, they develop into collections of blood that form cysts, spots, or patches. As the cycle continues these lesions may grow or reseed. They are not cancerous, but they can develop to the point that they cause obstruction or adhesions (web-like scar tissue) that attach to nearby organs, causing pain, inflammation, and sometimes infertility.
Endometriosis accounts for up to 30% of all female infertility cases, and up to 40% of women with endometriosis are infertile.
Endometriosis causes infertility in a number of ways. Endometrial cysts or implants in the ovaries or fallopian tubes are particularly likely to cause infertility. Endometrial cysts in the fallopian tubes may block the egg’s passage or they may grow in the ovaries and prevent the release of the egg. Sometimes infertility occurs when adhesions form rigid webs of scar tissue between the uterus, ovaries, and fallopian tubes, thereby preventing the transfer of the egg to the tube. Endometriosis can be associated with infertility even if the condition is mild.
More recent studies show that women with endometriosis have specific defects in the immune system that allow endometriosis to grow outside the uterus, and in turn, can lead to infertility. Despite these immune system defects, a woman’s immune system continues an ineffective fight against the endometriosis with the casualties of this fight being the egg that ovulates from the ovary and sperm in the fallopian tube thus infertility.
In the past, patients who have infertility and endometriosis were typically first treated with surgery to destroy all the endometriosis that is visible. Elegant studies in 1998 and 1999 showed that the monthly pregnancy rates in women with endometriosis and no surgery was 2% per month and after surgery 4% per month (25% per month is considered normal for a healthy couple). This of course is not a big improvement in pregnancy rates particularly considering it required a surgery and cost of greater than $10,000.
Ovulation induction and intrauterine insemination can help patients with endometriosis but is limited as the eggs and sperm are still easily destroyed by the inflammation from the endometriosis, resulting in pregnancy rates per treatment cycle 50% lower than other infertile patients without endometriosis.
In- vitro fertilization (IVF) is the great equalizer in patients with endometriosis as it allows the eggs to be removed from the body before they are exposed to the inflammation. The sperm is also not exposed to the inflammation and resulting embryos are placed back into the uterus where the tissue is normal and inflammation is not present. Resultant pregnancy rates are equal to other patients with infertility because the process of IVF has eliminated exposure of the eggs and sperm to the inflammation and the pathophysiology of endometriosis.
At Coastal Fertility Specialists we complete an infertility evaluation to make sure there is not a second cause of infertility. If the remainder of the evaluation is normal and the only diagnosis is mild to moderate endometriosis, we would typically recommend starting with simpler forms of treatment such as ovulation induction and intrauterine insemination. If that is unsuccessful or if there is moderate to severe endometriosis, we would then typically recommend proceeding to in-vitro fertilization treatment, which provides very high pregnancy rates.