Sudden bleeding 40 days after cesarean section may be related to normal menstrual flow, poor uterine repair, inflammatory infection and other causes. At this time, you need to go to the hospital for abdominal ultrasound examination to clarify the cause and then carry out targeted treatment. Common causes and treatments 1, normal menstrual flow: the time of menstruation after childbirth varies from person to person, some people have a better constitution, the body recovers quickly and menstruation recovers relatively early. At this time, if there is no other symptoms such as abnormal color of the leucorrhoea, odor, etc., consider the bleeding as a normal menstrual flow. At this time, you can observe first, if the blood volume is too large or continuous bleeding, you need to go to the hospital for ultrasound examination; 2. Poor uterine repair: postpartum weakness, lack of rest and other reasons can lead to poor repair of the contact surface of the uterine cavity and placental tissue, if the blood sinus is open, it can cause bleeding. At this time, you can take motherwort granules under the guidance of professional doctors to promote uterine contraction; 3, inflammatory infection: such as endometritis, pathogenic bacteria up to the endometrium, triggering inflammation. In addition to bleeding, it can be accompanied by pain in the pelvic region, abnormal leucorrhea, fever and other symptoms. The disease is often treated with drugs such as clindamycin and gentamicin. Patients need to pay attention to the cleanliness of the vulva and change their intimate clothing regularly. Note that after delivery the mother is weak, at this time should try to avoid sexual life to avoid cross-infection. In addition, you can eat more fresh fruits and vegetables, such as grapes, tomatoes, etc., and drink more water. Pay attention to personal cleanliness and hygiene, prevent infection, change and wash the inner clothes regularly, wash with warm water often, keep the vulva clean.