Did she undergo an Ultrasound examination? Is she having excessive bleeding or pain during her periods?How long is the abdominal distension there? The most common causes of uterus enlargement are fibroids(Harmless tumour) and adenomyosis(presence of tissue that lines the uterine cavity in the muscular wall) And both of them causes excessive pain and bleeding during menstruation..The treatment to both this depends on the severity of the disease and also the age of the patient.Surgeries like myomectomy(removal of fibroids alone) and hysterectomy(removal of uterus) are usually the treatment.Hysterectomy or uterus removal is done in severe cases and is the last resort..The choices regarding treatment of uterine fibroids are guided by the medical problems the fibroids are causing, your desire to have children, and your feelings and thoughts about surgery. I think it is helpful for you to know all of the options available. Fibroids almost never need urgent or immediate treatment.If it is a cancer of uterus,which is more commonly seen after 45,then uterus will have to be removed. And you can discuss with your doctor regarding the other treatment options since fertility is an issue here.