Consult your health care professional about the risks of taking this medicine for your condition before starting on a course with this medicine. Premarin increases the chances of getting cancer of the uterus. Vaginal bleeding after menopause may be a warning sign of cancer of the uterus. Your health care provider should check any unusual vaginal bleeding to find out the cause. Do not use Premarin with/without progestins (ex: medroxyprogesterone)