What causes fluid in the uterus for postmenopausal women?

Fluid in the uterus for postmenopausal women can be caused by several factors, including hormonal changes, particularly a decline in estrogen levels, which can lead to endometrial atrophy. Other potential causes include uterine polyps, fibroids, or infections, as well as fluid accumulation due to conditions like endometrial hyperplasia. In some cases, it may indicate more serious issues, such as endometrial cancer, so medical evaluation is important to determine the underlying cause.