Placenta previa

Placenta previa
[Summary]



Normal placenta attached to the posterior wall of the uterus, or anterior wall. If the placenta attached to the lower uterine segment, and even the lower edge to the placenta or cervix, mouth covered, with the first open fetal position below the Department, called placenta previa (placenta previa). Placenta previa hemorrhage late pregnancy is one of the main reasons is a serious complication of pregnancy, improper handling can endanger the lives of mother and infant safety. Its incidence to reports 0.24% to 1.57%, 1.0% reported abroad. In patients with placenta previa 85% to 90% of the mothers, especially more maternal, its incidence can be as high as 5%.



[Diagnosis]




1. History of late pregnancy or labor, suddenly no incentive painless repeated vaginal bleeding, placenta previa should consider, if the bleeding early, the amount is entirely of the possibility of placenta previa.

2. Signs vary according to blood loss, many bleeding, anemia was Maung Aye, acute massive bleeding, shock. In addition to first open fetal sometimes floating high, normal pregnancy abdominal examination and the same. Excessive bleeding, there will be the fetal hypoxia, severe cases of intrauterine fetal death. Sometimes in the pubic symphysis, the placenta may hear noises, but when the placenta attached to the posterior wall of the uterus when heard.

3. Vaginal examinations are typically only for consultation and vaginal see Konglongbu palpable consultation should not be in that neck of the consultation, so as to keep it attached to the placenta peeling caused bleeding. If the complete placenta previa, or even life-threatening. Vaginal examination applicable to the termination of pregnancy before a clear diagnosis and decision delivery. Must be in a transfusion, blood transfusion and surgery carried out only under the conditions. If the diagnosis has clearly should not be excessive bleeding or a vaginal examination. In recent years, widespread adoption of B-type ultrasonic examination has been very little further vaginal examinations.

Strict disinfection method used after vaginal Kuiqi genital examination to observe whether vaginal wall varicose veins, and cervical polyps, cervical cancer or other lesions caused bleeding. Gleaned after consultation with the primary showing, in the cervix that around two vaginal palpation Konglongbu lightly, if clearly palpable first disclosure of the fetal placenta previa can be ruled out, if exposed fingers between the first and fetal more The soft tissue thickness (placenta) should consider placenta previa. If I had cervical part of expansion, no active bleeding, can be lightly enter into cervical indicis to check for sponge-like tissue (placenta), as if the blood clots in contravention of the fragile. Attention to the cervix and placenta edge of the mouth, to determine the type of placenta previa. If the fetal membranes and decided to hit AA, fetal membranes can be shattered. Operation must be gentle, not from the placenta attached to the further isolation, to avoid bleeding. If bleeding occurred when checks should immediately stop inspections, the end of the purposes of cesarean section delivery.

4. Ultrasound B-type ultrasonic tomography can clearly see the uterine wall, the Department of fetal first exposed, the location of the placenta and cervix and cervical placental edge in the mouth and further clarified the relationship between the type of placenta previa (Figure 1 ). Placenta positioning accuracy rate of more than 95 percent, and repeated inspections have been widely applied at home and abroad in recent years, largely replaced by other methods, such as radioisotope scanning position, contrast and other indirect placenta.








Figure 1 placenta previa Ultrasonography

B-mode ultrasound diagnosis of placenta previa they have to gestational age, the second trimester placenta occupy half of the uterine cavity area. Therefore, the placenta near the mouth or cervix, mouth covered more opportunities to the third trimester placenta of intrauterine reduced to the size of 1 / 3 or 1 / 4 at the same time lower formation and extension of the increase in population and cervical edge of the placenta of the gap, it seems the lower uterine segment in the uterus with the placenta can be changed to shift the location of the normal placenta. So if the second trimester of B-ultrasound examination revealed the placenta position low home, placenta previa not premature for the diagnosis, follow-up should be the absence of regular vaginal bleeding symptoms of pregnancy before 34 weeks do not normally make the diagnosis of placenta previa.

5. Post-natal examination of the placenta and fetal membranes prenatal hemorrhage, childbirth should be carefully examined the placenta is delivered, in order to verify the diagnosis. Front part of the dark purple old placental attachment of blood clots. If the fetal membranes rupture distance from the edge of the placenta <7 cm for partial placenta previa.


[Treatment]




Treatment principle is bleeding blood. Should be based on the number of vaginal bleeding, whether in shock, and gestational age, parity, the wrong position, whether fetal survival, such as whether labor decision.

1. Look forward to look forward to therapy in the treatment aims to ensure that pregnant women under the premise of Baotai security. Baotai is to extend gestational age, fetal to reach or even near term, thereby improving the survival rate of perinatal infant. Apply to 37 weeks of pregnancy or previous estimate of fetal weight <2300 g, little vaginal bleeding, patients generally good, fetal survival. Patients should be hospitalized for observation, absolute bed rest, the left decubitus that, as far as possible not to interfere with, the opportunity to reduce bleeding. Timing intermittent oxygen, three times a day, each one hour, improving fetal oxygen supply. Waiting for fetal growth, to maintain the pregnancy to 36 weeks. In the waiting process, close attention should be bleeding with blood reserve, it would give the drug sedatives and blood, if necessary, to contractions inhibitors, such as salbutamol sulphate Ling, such as magnesium sulfate. Looking forward to the course of treatment, examinations should be carried out to confirm the diagnosis. If the diagnosis of partial or complete placenta previa, must continue to be hospitalized. In the hospital for observation, but also in accordance with pre-production phase and B-mode ultrasonography biparietal diameter measurement estimated fetal maturity. If the large number of observation during vaginal bleeding or repeated bloodshed, we must terminate the pregnancy.

2. Termination of pregnancy

(1) cesarean section: Cesarean delivery can be quickly concluded, the fetus is delivered in a short period of time, both mother and infant security is handling the primary means of placenta previa.

Must complete placenta previa cesarean section to the end of maternity leave, some of the early maternal or marginal placenta previa, in recent years, also tend to cesarean section. Decisively to timely cesarean section, to put an immediate end to childbirth, to achieve the purpose of rapid hemostasis. Reduce the trauma to the fetus, reducing the rate of perinatal infant, and under a deal with the post-partum bleeding, placenta previa is the most secure handling the most effective way of dealing with placenta previa is severe bleeding of the emergency measures.

Preoperative should actively correct shock, transfusion, transfusion of blood volume added that these measures will not only save patients, but also improve the intrauterine fetal hypoxia in the state.

Cesarean section more choices lower uterine segment incision, in principle, be avoided placenta, placental attachment surgery should be based on location identified. Preoperative B-mode ultrasonography placental attachment checking to determine location. If the placenta attached to the posterior wall, so the lower transverse incision; placenta attached to the anterior wall, do the following paragraph longitudinal incision. If the placenta attached to the uterine incision site, the placenta should be open AA.

Because of the lower uterine contractility poor, the baby is delivered, the placenta that is not delivered, to be timely for manual stripping, and uterine muscle wall injection lysergic new base increased from 0.2 to 0.4 mg of uterine contraction paragraph, together with uterine massage can reduce postpartum the amount of bleeding.

(2) of the vagina Wen: applies only marginal placenta previa, pillow to reveal, not bloodshed, in a short period of time can be estimated to the end of maternity leave. Decision after vaginal delivery, artificial AA, AA dropped after fetal head oppression achieve hemostasis placenta, and promote uterine contraction and speed up delivery. If the AA after the first disclosure decline is not satisfactory, still bleeding, or childbirth do not progress smoothly, and should be immediately diverted to cesarean section.

(3) transferred to the emergency treatment: If a large number of vaginal bleeding, and deal with local unconditionally, intravenous infusion or transfusion, and disinfected under the vaginal packing to temporary oppression bleeding, and quickly escorted transfers treatment.

Whether or vaginal birth after cesarean section, be taken to correct anemia and the prevention of infection.


[Etiology:




It is not clear, the following factors may be relevant.

1. Uterine endometrial lesions such as the Department of puerperal infection, prolific, many curettage and cesarean section, caused Endometritis damaged or endometrium, uterine decidual vascular growth failure, when the fertilized egg implants, , the inadequate supply of blood, in order to expand the intake of adequate nutrition and placenta area, extended to lower uterine segment.

2. Placenta too large if the placenta twins area larger than single births to achieve the lower uterine segment. Twin incidence of placenta previa than twice as high as single births.

3. Placental abnormalities such as Vice placenta, the main body of the placenta in the womb, the placenta up to the Deputy uterine cervix in the last paragraph under the mouth.

4. Fertilized eggs trophoblast growth retardation when the fertilized eggs of uterine cavity, have yet to develop to the stage of implantation can continue to lower uterine segment implantation, and it formed the growth and development of placenta previa.


[Clinical]




1. Symptoms late pregnancy or during labor, there's no incentive painless repeated vaginal bleeding is the main symptoms of placenta previa, occasionally occurred in 20 weeks of pregnancy were about. Hemorrhage due to late pregnancy or labor after the lower segment gradually extended, cervical disappear, or cervical dilatation, and attached to the uterine cervix, mouth, or the placenta can not be extended accordingly, leading to the front part of the placenta separated from its attachment, sinusoids to rupture and hemorrhage. Generally small in the initial bloodshed, peeling, blood coagulation, bleeding can be temporarily suspended, and occasionally also the first time the amount of bleeding and more cases. With the extension of the uterus, bleeding often recurring, and the amount of bleeding, there are more. Vaginal bleeding occurred sooner or later time, the number of recurring bleeding of the number and type of placenta previa is very much related. Complete placenta previa often the initial hemorrhage earlier, about in about 28 weeks of pregnancy, the number of repeated bleeding frequent, more volume, and sometimes can make a massive bleeding in patients with a state of shock; marginal placenta previa from an enemy country in the initial later, in the more than 37 to 40 weeks of pregnancy or labor, was also less partial placenta previa initial bleeding time and the amount of bleeding between the two. Partial or marginal placenta previa patients with AA fetal first exposed to the oppression of the placenta, fetal AA if exposed to the rapid decline in direct oppression placenta, the bloodshed could be stopped.

As repeated vaginal bleeding or large, can occur in patients with anemia, thalassemia is proportional to the degree and amount of bleeding, and bleeding can be serious shock, fetal hypoxia occurred, the distress, or even death.

2. Signs of bleeding in patients with normal circumstances with the number may be, they have massive bleeding was pale, weak pulse, blood pressure decline shock phenomenon. Abdominal examination: uterine size and number of weeks in line with menopause due to lower segment occupy a placenta, fetal effects to reveal Rupen, the first disclosure of the floating high, with about 15% of the wrong position to abnormal, particularly for breech presentation. Labor check: for paroxysmal contractions, intermittent period uterus can be completely relaxed. Sometimes can be heard above the pubic symphysis placenta murmur.


[Diagnosis]




Major bleeding late pregnancy with placental abruption identification; other reasons for the prenatal bleeding, such as fan-shaped front placental vascular rupture, placental edge sinusoids rupture and cervical lesions such as polyps, erosion, cervical, vaginal examination of history through , B-type ultrasonic inspection and placenta after delivery checks to be confirmed.


[Prevention]




Do a good job in family planning, promotion of contraception to prevent the prolific and avoid repeated curettage or intrauterine infection, in order to avoid injury or endometrial Endometritis. Strengthening prenatal checks and missionary, bleeding during pregnancy, regardless of how many are required amount of bleeding and timely medical treatment, to achieve early diagnosis and proper treatment.