Ultrasonic demonstration of endometrial fluid collections unassociated with pregnancy.

Intrauterine fluid collections were demonstrated by ultrasound in 17 non-pregnant patients. In nearly all instances, the surrounding echoes were of low to moderate amplitude. This has been noted previously in women with an ectopic or abnormal intrauterine pregnancy. In 2 patients, a well-defined thick rind of high-amplitude echoes encompassed the fluid, simulating an early gestational sac. Small intrauterine fluid collections were seen most frequently in non-pregnant patients who had vaginal bleeding or inflammation of the endometrium or adnexa.