Endometriosis and Your Fertility
Understanding the condition and its treatment
How Endometriosis Works
Every month when a woman has a period, the cells that line the uterus, known as the endometrium, are shed in the menstrual flow. Some small portion of this combination of blood and endometrial cells may also pass out through the fallopian tubes into the abdominal cavity. Most of the time, the body’s natural defense systems attack and destroy these cells before they can begin to grow. However, for reasons that are not clear, this is not always the case.
In certain individuals, these endometrial cells actually implant on structures in the abdominal cavity and begin to grow. This is endometriosis: the presence of viable endometrial cells in places other than the uterine cavity. Then, each month when the normal hormonal changes result in a menstrual period, much the same change occurs in the endometriosis. A small amount of bleeding occurs from the endometriosis cells. This is very irritating to the body, and as a result of this, scarring occurs around the endometriosis. Most often this is a progressive process, with a small additional amount of bleeding and scarring occurring every month.
Once the endometrial cells begin to grow in the abdominal cavity, they are known as implants. Implants can occur on any structure, including the ovaries, fallopian tubes, bladder, bowel, and on the lining of the abdominal cavity (known as the peritoneum). The area behind the uterus, between it and the rectum, is known as the cul-de-sac, and this is the most common site for endometriosis. Implants may appear as small, clear or red, fluid-filled sacs, or most commonly, as dark brown or black areas. The collection of old blood in the implants gives them this appearance. Some scarring is typical around the implants, and can be very localized or, at times, quite severe. When endometriosis develops in the ovaries, large cysts full of old blood, known as chocolate cysts or endometriomas, may result.
There are other theories as to how endometriosis develops, and this scenario (known as retrograde menstruation) certainly cannot explain all cases of endometriosis. It is, however, the most widely held theory and does explain all but the most unusual cases of endometriosis.
Although in some individuals endometriosis may cause no symptoms, it is typically associated with two problems: difficulty conceiving and pain.
The pain may be present as extremely painful menstrual periods. This pain with periods, known as dysmenorrhea, often becomes worse as a woman gets older. Pain with intercourse is not uncommon in women with endometriosis, and there may even be pain that persists throughout the month but is worse during periods.
Not everyone with endometriosis has pain; in fact, there is little correlation between the amount of endometriosis an individual has and the amount of pain she experiences. Sometimes a single, small implant may cause excruciating pain, while someone with severe disease may be pain free.
The association of endometriosis with difficulty conceiving has long been known, and research shows many different ways in which endometriosis interferes with normal conception. Endometrial implants are irritating to the body, and as a result, the body produces a group of substances known as prostaglandins. Prostaglandins can alter not only the maturation and development of the egg within the ovary, but also the release of the egg from the ovary.
The ability of the fallopian tube to function normally may also be impaired. Whereas in “nature’s way” the tube is poised and ready to pick up an egg if one appears on the surface of the ovary, in the presence of endometriosis the tube may be “lazy” or “floppy.” Not only is the overall tone of the tube decreased, but the fimbria, which are responsible for egg pickup, may end up being very far from the ovary itself. The combination of these factors may make it very difficult for the tube to pick the egg up off the surface of the ovary. Thus, even if ovulation does occur, the egg may not get into the fallopian tube.
Endometrial implants also result in the increased production and activation of a group of cells known as macrophages. Macrophages are part of the body’s natural defense system and can be visualized as little “Pac-men,” actively attacking and destroying any cells that they encounter. In women with endometriosis, macrophages attack and destroy sperm cells more than normal, thus making it more difficult for the sperm to reach and fertilize the egg. The macrophages may also interfere with tubal function, ovarian function, and perhaps even early embryo development.
It is important to keep in mind the number and variety of ways endometriosis affects fertility, particularly when discussing the ways of treating endometriosis.
It is not clear why endometriosis occurs in some individuals and not in others, but about 10 to 20 percent of all reproductive-age females have been found to have endometriosis. In women with infertility, this number may be as high as 30 to 50 percent. Factors associated with the development of endometriosis include delayed childbearing, long periods of menstrual cycles uninterrupted by pregnancies or birth control pill use, abnormal pelvic anatomy, and stress. Many other factors have been associated with the development of endometriosis and there is even a genetic factor, meaning that you may inherit an increased likelihood of developing this process if a close relative has it.
A physician can often suspect endometriosis on the basis of a history and physical exam. A history of progressively worsening pain with menstrual periods is suggestive. A history of cramping that begins two to three days before the onset of menstrual bleeding is also common with endometriosis, as is deep dyspareunia (pain with deep penetration during intercourse). During the physical exam, the physician may be able to feel endometriosis, particularly if it is in the cul-de-sac. Endometriosis is not visible by ultrasound unless there is ovarian involvement; endometriomas (fluid collections near the ovary) are visible by ultrasound. If significant endometriosis is present, the combination of a history, pelvic exam, and ultrasound will reveal it.
There are tremendous variations in the amount of endometriosis an individual may have. The American Society for Reproductive Medicine has developed a grading system for quantifying the amount of endometriosis present, recording the size, number, location, and character (filmy versus dense, deep versus superficial) of implants.
The only way to definitively diagnose endometriosis is by visualizing it. With a laparoscopy, the surgeon notes the endometriosis present and any adhesions or scarring that may have formed. These findings are recorded on the classification sheet and a score assigned. That score is then used to determine the grade of disease, on the scale of: I = minimal, II = mild, III = moderate, and IV = severe. While there are many limitations to this system of classification, it does provide a way to compare the extent of endometriosis from patient to patient and may be useful in prognosticating about the chances of conceiving.
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