If there is no abdominal pain but sudden bleeding in the middle of pregnancy, placenta praevia, cervicitis, cervical polyps, cervical tumors, etc. should be considered. 1. Placenta praevia: refers to the position of the placenta is lower than the prenatal exposure, and its edge reaches or covers the cervical opening, the clinical manifestation is painless recurrent vaginal bleeding without any causative factors. 2. Cervicitis: pregnancy combined with cervicitis may have cervical congestion, vaginal bleeding, during the period of vulvar itching and other symptoms, due to the invasion of the surrounding tissues, with the development of the disease, leading to the emergence of frequent urination, painful urination, urinary difficulties and other symptoms. 3. Cervical polyp: it can be seen by vaginal speculum examination and there will be painless vaginal bleeding. 4. Cervical cancer: contact bleeding can occur when pregnancy is combined with cervical cancer, and cytologic examination of cervical cancer is needed. It is recommended that pregnant women should take obstetric checkups on time, consult a professional doctor if vaginal bleeding occurs, do relevant examinations and take professional measures to intervene in time.