When it comes to “gender reassignment”, people often think of gender swapping between men and women. Many people do not know that in fact, fibroids can also become “transgender”. Generally speaking, uterine fibroids are benign tumors, and their “sex change” may or may not worsen the condition or even become cancerous. Degeneration of fibroids is more likely to occur when the growth of fibroids is accelerated and blood flow is relatively insufficient, such as during pregnancy, after childbirth and after menopause. In most cases, this “degeneration” is a degenerative change that does not aggravate the patient’s condition. Through ultrasound, the doctor can detect changes in the shape of the fibroids, such as softness and transparency, mostly glassy; becoming like a deflated ball and forming a cystic cavity, mostly cystic; becoming as hard as a stone, probably fatty or calcified. This type of “degeneration” is not a cause for concern for patients. However, there are two types of “degeneration” that must be taken seriously: one is red degeneration. This is the case of the pregnant woman mentioned above. Most of the red degeneration of uterine fibroids occurs during pregnancy, but it can also occur after delivery. It is mostly caused by necrosis and bleeding of fibroids due to acute ischemia, and the fibroid tissue is dyed red. This “degeneration” is often accompanied by severe abdominal pain and may induce miscarriage or preterm delivery. For this reason, women with fibroids over 4 cm in diameter are generally advised to remove the fibroids before pregnancy. Another type of fibroids is malignant transformation, which is cancerous. Fortunately, it is generally believed that the chance of fibroids becoming cancerous is less than 0.5%, which means that one out of every 200 cases of fibroids may become cancerous. Generally speaking, those fibroids that grow suddenly in a short period of time or grow instead of shrinking after menopause are the ones that require the most vigilance. For fibroids that grow slowly and do not change much over time, the possibility of malignancy is relatively small. Uterine fibroids are very common, and women can “live with them”. Generally speaking, if there are no symptoms such as excessive menstrual flow, pain, difficulty in urination, anemia, etc., fibroids with a diameter of less than 3 cm only need to be monitored by ultrasound or pelvic examination every 3-6 months. However, if there are single fibroids larger than 5 cm in diameter, the volume of the uterus when not pregnant because the fibroids are larger than 2~3 months of pregnancy, or the fibroids are in a special location, it is recommended to remove them by surgery as soon as possible.