Bleeding after 15 days of intercourse is not necessarily caused by pregnancy, because pregnancy is manifested by delayed menstruation, and the possibility of pregnancy will be greater if it is delayed for more than a week. Use early pregnancy test paper, pregnancy test or come to the hospital to draw blood to determine the situation of pregnancy. There may also be a small amount of bleeding if the endometrial lining is partially exfoliated and bleeding before the upcoming period, or if there are endometrial polyps or thickening of the endometrium, or cervical canal polyps. Cervical erosion or chronic cervicitis may also have symptoms of bleeding during non-menstrual periods, so a small amount of bleeding 15 days after intercourse does not necessarily mean that it is a symptom of pregnancy, this specificity is very poor, it is best to come to the hospital for a blood test for HCG, which is the gold standard that can rule out pregnancy.