A small amount of bleeding during pregnancy may be a normal physiological phenomenon caused by the fertilized egg coming to term, or it may be an abnormal bleeding caused by a pre-eclampsia, etc. A timely visit to the hospital is required for differential diagnosis through ultrasound examination. The causes of bleeding during pregnancy can be judged by the week of pregnancy and accompanying symptoms. 1. Early pregnancy: If the bleeding is in early pregnancy, accompanied by nausea, vomiting and change in diet, it can be considered as bleeding caused by fertilized egg implantation, which can usually be relieved by itself. If vaginal bleeding is accompanied by slight abdominal pain, it is considered to be preterm abortion caused by insufficient ovarian secretion of progesterone level, which requires bed rest and medication such as dydrogesterone for fetal preservation treatment under the guidance of a doctor. If it is accompanied by obvious symptoms of pain on one side of the lower abdomen, it should be considered whether ectopic pregnancy rupture bleeding has occurred, which can be further diagnosed through ultrasound examination and suitable treatment methods can be chosen according to the specific condition; 2. Mid-pregnancy: a small amount of bleeding in mid-pregnancy, mostly seen in the placenta low placement, can easily lead to premature birth, miscarriage and other consequences, which should be paid attention to. Pregnant women need to rest in bed and reduce activities as much as possible. If the bleeding symptoms persist and cannot be relieved, they should seek medical attention and terminate the pregnancy if necessary; 3. Late pregnancy: a small amount of bleeding in late pregnancy should be considered for placenta praevia or placental abruption. If there is only a small amount of bleeding and no other uncomfortable symptoms, conservative treatment can be carried out, such as giving corticosteroids to promote fetal lung maturation. If the opening of the uterus has been opened wide, the fetus should be delivered by cesarean section as soon as possible to avoid intrauterine distress and endangering the life of the fetus.