The cause of uterine fibroids is not yet explained. However, a lot of clinical data show that fibroids are closely related to high estrogen level in the body and long-term estrogen stimulation. Uterine fibroids are mostly seen in middle-aged women, but there is a trend of younger age of onset; 2. Uterine fibroids are often complicated by endometrial hyperplasia; 3. Ovarian granulosa cell tumor and follicular membrane cell tumor (which can secrete estrogen) are often combined with uterine fibroids; 4. The growth of uterine fibroids can be accelerated.