Your doctor’s first step will probably be to ask you some questions to see if there’s an obvious cause for the bleeding, like breakthrough bleeding after you just start to take a birth control pill. Your doctor will also want to know if you’re having pain during sex, which can be a sign of inadequate lubrication or infection, depending on when it happens. Your doctor will give you a pelvic exam and look for any source of the bleeding, like vaginal tears or lesions, signs of pelvic organ prolapse, cervical polyps, or inflammation. If your doctor finds any polyps, he or she might be able to remove them in the office and send them to a lab for testing, or make a later appointment to have them surgically removed. During a Pap test, your doctor can swab your cervix to test for sexually transmitted infections like chlamydia and gonorrhea, which can cause bleeding after sex and are treated with antibiotics. The Pap test also detects any sign of abnormal, precancerous growths or cancer cells.