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.