If bleeding occurs in the third trimester of pregnancy, even if it is persistent, or if it is heavier, it is important to go to the hospital for a checkup. The first thing to do is to do a routine gynecological examination. Secondly, you must have a progesterone test in time, and treat according to the results of the test. Because the bleeding may be due to cervical erosion and other reasons for bleeding, but it may also be the manifestation of preterm miscarriage, so we must be vigilant. The main symptom of preterm miscarriage is a small amount of bleeding from the vagina after pregnancy. Depending on the amount of bleeding and how long it has been accumulating in the vagina, the color of the bleeding can be bright red, pink or dark brown. Sometimes it is accompanied by a slight pain in the lower abdomen, but sometimes it is not, just a little drop feeling, or a feeling of back pain and bloating.