During a pelvic ultrasound, the technician remarked on spots in my uterus that she said are usually from implantation, miscarriage, or surgery. at the time, i had definitely never had any of those things. what else could be the cause?

Ultrasound ?'s: "Spots in uterus" by a technician doing a pelvic ultrasound with a negative history as described in your question, is usually b/c of an inexperienced technician , who should not be discussing those results with you in any case, as it is really the radiology physician who is best qualified to comment.

Unclear : We do not typically refer to findings on ultrasound as spots. I would recommend seeing a gynecologist who can evaluate the findings on the sonogram and place them in the proper clinical context. Then, the doctor can determine if any further workup is needed