Those things about pregnancy and childbirth: placenta previa

After receiving the ultrasound report, there are many things that scare expectant mothers, one of which is placenta previa. Can you give birth by yourself? Will it bleed? When will it bleed? Do you want to stay in bed? There is so much uncertainty, and each doctor’s statement is different, that expectant mothers do not know what to do.

The incidence of placenta previa varies, It has been reported that when ultrasound is performed at 11-14 weeks of pregnancy, The proportion of placenta margin reaching or covering the cervical internal orifice was 42%, By 20-24 weeks, the proportion was 3.9%, At full term, the proportion dropped further to 1.9%. Therefore, There is no need to worry about finding that the placenta is low during early pregnancy ultrasound examination. Because as the uterus grows, Most placenta positions will gradually move upward. However, if the placenta covers the internal opening more than 15 mm during the second trimester, The probability of placenta previa at term is significantly increased, Moreover, the greater the distance covering the cervical internal orifice, The higher the probability of cesarean section. Whether vaginal delivery is possible or not, Ultrasonography is also required at 35-36 weeks, Please note that, The gold standard for diagnosis of placenta previa is transvaginal ultrasound (TVS), Because the false positive rate of transabdominal ultrasound (TAS) is relatively high. If the distance between the placenta edge and the cervical internal orifice is more than 20 mm, Can transvaginal trial delivery, and the success rate of vaginal delivery is very high. If the distance between the placenta edge and the cervical internal orifice is between 0-20 mm, the probability of cesarean section will be relatively high, but there is still a chance of vaginal delivery, which depends on whether the patient has vaginal bleeding or other conditions before or during labor.

In the second and third trimester of pregnancy, Some patients with complete placenta previa or partial placenta previa will have bleeding, For a small amount of bleeding, There is no need to be hospitalized for observation for the time being, Because some studies have found that there is no significant difference in clinical outcomes between hospitalization and home observation. However, for patients with moderate or excessive bleeding, It is still safer to be hospitalized for observation. Even when hospitalized, there is no need for absolute bed rest. For patients with placenta previa whose fetus is not yet mature, some people have tried to use cervical cerclage to reduce bleeding and prolong gestational weeks, but the current evidence does not support this.

In placenta previa, the risk is relatively big is the last cesarean section history, placenta planted on the uterine scar, this kind of situation is easy to occur placenta accreta, in delivery is easy to lead to massive hemorrhage and hysterectomy. Encountered this kind of situation, must go to the big hospital with rescue conditions.

Author: Duan Tao

The article was reprinted by Clove Garden authorized by the author.