There are many reasons for the enlargement of the uterus. Clinically, the size of the normal uterus is nearly the size of an egg. The following are the most common reasons for the enlargement of the uterus: First, pregnancy may cause an enlarged uterus, accompanied by symptoms of early pregnancy. Secondly, the uterus can be enlarged due to occupational lesions, such as uterine fibroids, adenomyosis and hypertrophy, which can cause an increase in the size of the uterus and may be accompanied by prolonged menstruation, increased menstrual flow, dysmenorrhea and other uncomfortable symptoms. Third, malformation of uterine development can also cause uterine enlargement, such as saddle-shaped uterus or bicornuate uterus, which can cause an increase in uterine volume. If the uterus is enlarged, it is recommended to go to the hospital for relevant examinations, such as ultrasonography and MRI, which can determine the cause of the enlarged uterus through imaging.