If you have not had your period by the time it comes, but you find a small amount of bleeding on your underwear, it is advisable to rule out the following causes: First, you must rule out the possibility of pregnancy. In clinical practice, when someone has a small amount of vaginal bleeding when it is time to have a period, it is advisable to have a blood test for HCG, and if the blood HCG is >10mIU/mL, it indicates pregnancy. If the HCG is more than 10mIU/mL, it will indicate pregnancy. Whether the pregnancy is intrauterine or ectopic will need to be monitored by continued blood sampling. Secondly, clinically, it is necessary to exclude luteal insufficiency, which is often caused by irregular vaginal bleeding at the time of menstruation, often without lower abdominal pain. Thirdly, we need to exclude the possibility of inflammation, endometrial inflammation, cervical inflammation, pelvic inflammation, all of which may result in small amount of vaginal bleeding. It is suggested that clinical examination by gynecological examination can exclude the possibility of inflammation.