What are the risks of keeping a very large fibroid without removing it or without removing the uterus ? the fibroid is not causing major problems

Depends: Depends on size. Fibroids should only be removed if they are symptomatic. Symptoms include heavy periods, pelvic pain, bladder or bowel symptoms. If the fibroid is asymptomatic we generally worry when the uterus starts to get larger than a 14 week size pregnant uterus as if can theoretically press on other organs and removing the uterus / fibroid may be more difficult. But that is not absolute.