Uterine fibroids in pregnant women usually do not go away on their own, but most of them are in a stable state, and a few of them will continue to grow or degenerate, and if the tumor is large enough to affect the mother and child, or if degeneration occurs, it can be surgically removed or treated with drugs. The cause of uterine fibroids is not yet known, but clinical observation shows that the disease occurs in the reproductive period, and it is very rare in postmenopausal and pre-pubertal period, so it is considered to be related to the high level of estrogen. In addition, it has been found that progesterone can also promote the mitosis and growth of leiomyoma. And after pregnancy the estrogen and progesterone in the body are significantly higher compared to pre-pregnancy, so fibroids will not be eliminated under the influence of hormones. Although uterine fibroids will not be eliminated during pregnancy, most of them are relatively smooth and have no effect on mother and child, and generally do not require special treatment. A small number of fibroids may continue to grow under the influence of high estrogen and progesterone, and may require surgery during pregnancy if their size is large enough to affect the development of the fetus. During pregnancy, due to the increase of uterus and hormone level, some fibroids may have red degeneration, and the size of fibroids will increase, and pregnant women may also have nausea, vomiting, fever, abdominal pain, etc. At this time, it is necessary to take anti-infective, rehydration and other supportive treatments. Pregnant women with uterine fibroids should pay attention to a light diet, appropriate weight control, and close follow-up during pregnancy to dynamically observe the changes of fibroids, and consult the doctor at any time if there is any discomfort.