Adenomyosis is a disorder in which the cells that line the uterus (the endometrium) begin to invade the muscle of the uterus (the myometrium). This generally occurs in women of late childbearing years who have already experienced pregnancies. Here’s a look at the causes and risk factors of adenomyosis.
What causes adenomyosis?
Experts are still unsure as to the reasons why adenomyosis develops. There are, however, several educated premises regarding its appearance. Because some doctors have noticed that it is common among women who have undergone cesarean sections or other procedures involving uterine incisions, one suggestion is that the endometrial cells lining the inside of the uterus essentially gets into the myometrium through these incisions. The endometrial cells appear to be invasive, and this growth continues -- much like bacteria can enter the blood or body through an open cut or wound. Alternatively, in the weeks following the birth of a child, if the uterine cells become inflamed, it may interfere with the normal borders of the uterine cells and linings.
Additionally, there appears to be a genetic link to adenomyosis. This has led to other theories surrounding the disease’s development. It is possible that when a fetus forms her uterus, endometrial cells wind up inside the myometrium, lying latent for many years. One of the newer proposals is that adenomyosis forms because bone marrow stem cells infringe on the myometrium.
How does adenomyosis happen?
Whichever of these theories lies closest to the truth, adenomyosis is highly linked to a woman’s estrogen levels and incumbent menstrual cycle. Without an exact cause, it is difficult to piece the entire process together. However, estrogen appears to encourage the spread of the misplaced cells, potentially making the situation worse on a monthly basis. In fact, even though the endometrial cells are in the wrong spot, they still want to perform their monthly duties of hardening, breaking down, and being shed -- the root of menstruation. This can make the uterus harden, causing dysmenorrhea, tenderness, and even miscarriage. Estrogen’s role in adenomyosis is in part made obvious by the fact that it tends to go away with menopause.
Who is at an increased risk for adenomyosis?
Several issues seem to increase the likelihood of developing adenomyosis or to occur commonly amongst women with adenomyosis. As mentioned, there appears to be a measure of genetic input in regards to its development. Adenomyosis tends to run in families. Age is also a factor -- adenomyosis is thought to occur more commonly in premenopausal women in their 40s or 50s. However, it is possible it is not as uncommon as was suspected it younger women; they simply do not notice the symptoms as severely as women passing out of middle age who have been subject to the disease for longer. The theories of the causes of adenomyosis also suggest women who experience uterine operations are more likely to develop this disorder.
