A bit of bleeding in the fourth month of pregnancy may be caused by pre-eclampsia, inevitable abortion, chronic cervicitis or cervical polyps, the specific causes and treatments are as follows: 1. Pre-eclampsia: It is seen in the low position of the placenta or mild separation of the fetal membranes, which is manifested as a small amount of vaginal bleeding, sometimes accompanied by the phenomenon of abdominal pain. In addition, severe constipation, frequent diarrhea, and excessive emotional tension are also likely to stimulate the appearance of miscarriage. You should pay attention to rest and keep warm, avoid staying up all night, and take oral medication under doctor’s guidance to protect the fetus, such as progesterone and dydrogesterone tablets. If the placenta position is low, it is necessary to review the ultrasound after 1 month, and most of the placenta position can be elevated; 2, inevitable miscarriage: manifested as more and more vaginal bleeding, and the cervical opening is found to be blocked with embryonic tissues on examination, and it is necessary to remove intrauterine gestational tissues in order to stop the bleeding in time, and the uterus needs to be cleansed and processed if necessary, and the uterus needs to be cleansed and treated with medication according to the maternal condition; 3, chronic cervicitis: due to the stimulation of cervical mucosal mucosal cells by the inflammatory disease The cells of the cervix are stimulated by inflammation, and there will be abnormal bleeding from the vagina, which can be treated with oral gynecological Qianjin tablets and Huanglianxin tablets under the guidance of the doctor; 4, cervical polyps: it may be due to the stimulation of long-term inflammation, so that the cervical mucous membrane is over-hyperplasia, and polyps are formed by protruding gradually towards the cervical opening, and if intercourse occurs, there may be vaginal bleeding. In this case, if the condition of the pregnant woman allows, you can take the polyp removal surgery, to avoid the recurrence of bleeding.