Hello, In the current scenario, the causes for this spotting could be local like vaginitis, cervicitis, polyps, endometritis, erosions of the cervix, hormone imbalances, weight changes, stress, general infections and medications. Pregnancy is a remote possibility if you have been sterilized for some time. Please go ahead with a complete clinical evaluation, get a pap smear, swab tests if needed, urinalysis, trans-vaginal sonogram and hormone assays if required. Maintain a healthy weight, regular exercise and a healthy diet. Hope this helps.