What is considered a prominent endometrial stripe?

Depends: Will depend what your provider means. Prominent could refer to stripe thickeness or brightness on sono but usually thickness. Much more of an issue in women after menopause where thickness could be a sign of abnormal tissue buildup. In younger women on pills/patches/iud stripe should be thin. Not on hormones the stripe will vary by time of month. Most prominent before cycle.Can be seen with polyps

Not reliable: This description is not very reliable. The endometrial stripe is helpful to describe in a menopausal women and has been studied related to fertility. It is normal in your age range for the endometrium to be thinner after a period (4mm) and then thicken thru the month until menstruation. Up to 20mm may be normal. If you are having problems with heavy or irregular bleeding, then have a biopsy.