If the placenta is low in the 14th week of pregnancy and there is vaginal bleeding, it should be treated with fetal preservation, prohibit coitus, keep the bowels clear, pay attention to rest, and avoid walking for a long time. Before the 28th week of pregnancy, with the increase of gestational weeks, the area of the uterine cavity continues to increase, although the placenta is also gradually increasing, but not as fast as the increase of the uterine cavity, most of the placenta position will be relatively upward, such as vaginal bleeding, should be given birth control treatment, avoid coitus, pay attention to rest, avoid walking for a long time, keep stools unobstructed, and regular ultrasound to monitor the position of the placenta. Placenta previa is a common cause of bleeding in mid-pregnancy, and its common symptom is painless bleeding, if there is a large amount of vaginal bleeding, it is recommended to consult a hospital in time.