In early pregnancy, there are symptoms of bleeding in the vagina, but there is no obvious abdominal pain. The reasons for the appearance of this symptom may be: i. Pre-eclampsia symptoms due to insufficient level of progesterone secreted by the corpus luteum of the ovary; ii. Abnormal development of the embryo due to various harmful factors, resulting in symptoms of miscarriage; iii. Patients suffering from gynecological diseases such as cervical polyps and cervical erosion, and bleeding from these lesions; iv. Uterine lesions such as endometrial polyps and submucosal fibroids, which also can experience painless vaginal bleeding during pregnancy. If treatment is not carried out in time, it will eventually cause miscarriage. Pregnant women need to go to the hospital as soon as possible with the help of their family members for relevant examinations, clear diagnosis and timely treatment.