The normal placenta position should be attached to the anterior wall, posterior wall, side wall of the uterus, and the body part of the uterus. After 28 weeks of gestation, if the placenta attaches to the lower end of the uterus, the position is lower than the lowest position of the fetus, and the lower edge of the placenta reaches or completely covers the inner cervical opening, which is clinically called the placenta previa. Placenta previa is one of the most serious complications of pregnancy, and the most common cause of major bleeding in the third trimester of pregnancy, which can be divided into central placenta previa, partial placenta previa or marginal placenta previa according to the location relationship between the placenta and the internal orifice of the cervix.
The dangerous placenta previa is a special and more dangerous placenta previa, which refers to a previous caesarean section or uterine surgery, and this pregnancy is not only placenta previa, but also the placenta is attached to the original surgical scar area. Villi implanted into the muscle layer of the uterus, and even penetrate the muscle layer of the uterus, reaching the bladder, the placenta is difficult to peel during surgery, resulting in massive bleeding, difficulty in hemostasis, and easy to cause fatal bleeding. In severe cases, the lives of pregnant women are endangered. Call it the dangerous placenta previa.
The reason why it is called dangerous placenta previa is mainly because it is easy to cause heavy bleeding during pregnancy, and in caesarean section delivery, the uterus is often removed because the bleeding is difficult to stop, and even seriously threatens the safety of maternal life.
If the placenta is found to be attached to the uterine incision during the pregnancy obstetric examination, it is necessary to do a B ultrasound review or mriori resonance to determine whether it is a dangerous placenta previa, and if it is determined that it is a dangerous placenta previa, the appropriate time for caesarean section should be selected. Dangerous placenta previa avoids emergency surgery as much as possible, and a plan for delivery needs to be made in advance in the third trimester. Termination of pregnancy between 34 and 37 weeks is generally recommended, depending on the severity of the lesion. If there is no bleeding, try to terminate the pregnancy at 36 weeks of pregnancy. However, if heavy bleeding occurs during pregnancy, surgery is required to terminate the pregnancy immediately, regardless of the week of pregnancy. It is also important to go to a hospital with experience in the treatment to give birth and be fully prepared before the operation can be performed.
However, with the continuous development of medicine, the preservation of uterine surgery program is constantly improving, the application of various hemostasis techniques, the development of uterine vascular ligation, interventional treatment, the possibility of preserving the uterus is also very large, therefore, the dangerous placenta previa pregnant women do not have to be too nervous, actively cooperate with the doctor's treatment, do not stress too much.
Therefore, if there are no special circumstances, it can be delivered smoothly and reduce the occurrence of dangerous placenta previa.