Could an IUD cause endometrial cancer?

No, the opposite! An IUD is an intra-uterine device, an extremely effective method of contraception. Endometrial cancer is most often caused by exposure of the body to lots of estrogen. Because the IUD either contains no hormones or contains progesterone, it does not cause endometrial cancer. In fact, progestogen containing iuds (such as the mirena) may protect against endometrial cancer.
Endometrial cancer. Progesterone iuds can actually be used to treat endometrial cancers in very highly selected patients.

Related Questions

Could endometrial cancer cause Fever that lasts for a week or more?

It depends. Any Fever that persists beyond one week raises questions about something serious going on. If your Temp is over 100F for more than one week, you should go see your doctor for a complete physical examination to find the cause. Endometrial cancer rarely causes fever unless it has spread out into liver which would be uncommon, but it depends on details of your medical history.

Could you develop endometrial cancer randomly?

Yes. Even common endometrial adenocarcinoma, for which risk-factors (genetic and environmental) are well-known, can pop up in most any grown woman at any time. Much is simply dumb luck -- which genes just happened to get hit.

How could biopsy for endometrial cancer be benign and then ten months later show cancwr? First one was wrong maybe?

Transformation. Most malignancies begin in a field effect. Well known that many transforming cells appear normal on bx and with time the phenotypic features begin to evolve. Endometrial bx may initially at sites taken appear normal but with q 10 mo. Interval these same cells are now malignant in appearance, especially if bx as symptoms progress.
You had 2 biopsies? Cancer can develop very fast in the uterus. I'm not at all surprised that this happened. If you want your biopsies reviewed and signed by a few more pathologists, you're within your rights. Your physician can have it arranged.