Thank you very much for your time....
Hi,
In postmenopausal women, endometrial stripe measurements by transvaginal ultrasonography are used to exclude endometrial neoplasia. Limited information exists on the use of endometrial stripe measurements for premenopausal women.1,2 Endometrial thickness varies throughout the menstrual cycle; thus, a thickened stripe may not indicate pathology.
We hypothesized that a transvaginal endometrial stripe of less than 5 mm in premenopausal women would exclude endometrial polyps and intracavitary leiomyomata, thereby eliminating the need for sonohysterography.
ref: http://www.greenjournal.org/cgi/content/full/104/1/120
So this study suggests that there could be uterine pathology-tumor/mass could be present but further investigations are required along with your clinical history before any conclusion can be made.