Placental abruption

Introduction After 20 weeks of gestation or during childbirth, the placenta in the normal position is partially or completely detached from the uterine wall before the delivery of the fetus, called placental abruption. Placental abruption is a serious complication in the third trimester of pregnancy. The onset is urgent and progresses rapidly. If it is not treated in time, it can endanger the mother and child. The incidence of domestic reports is 4.6 to 21 , and the incidence rate abroad is 5.1 to 23.3 . The incidence is related to whether the placenta is carefully examined after delivery. Some patients with mild placental abruption can have no obvious symptoms before labor. Only when the placenta is examined after delivery, it is found that there is clot blockage in the early exfoliation. Such patients are easily overlooked.

Cause

The pathogenesis of placental abruption has not been fully elucidated, and its onset may be related to the following factors.

1. Vascular lesions Placental abruption in pregnant women with severe pregnancy-induced hypertension, chronic hypertension and chronic kidney disease, especially in patients with systemic vascular disease. When the sacral sacral small artery is spasm or hardened, causing avascular necrosis of the distal capillary to cause hemorrhage, the blood flows to the sacral layer to form a hematoma, which causes the placenta to peel off from the uterine wall.

2. Mechanical factors (especially the direct impact of the abdomen or the fall of the abdomen directly contact the ground, etc.), the extraversion of the correction of the fetal position, the umbilical cord is too short or the umbilical cord around the neck, the first exposed part of the fetus during childbirth, may be Promote placental abruption. In addition, the first fetus in a twin pregnancy is delivered too fast or the amniotic fluid is too much in the rupture of the membrane when the amniotic fluid flows out too quickly, so that the intrauterine pressure suddenly drops, and the uterus suddenly contracts, which may also cause the placenta to peel off from the uterine wall.

3. Sudden increase in uterine venous pressure In the third trimester of pregnancy or after labor, when the pregnant woman takes the supine position for a long time, supine hypotension syndrome may occur. At this time, due to the huge uterus compression of the inferior vena cava, the amount of blood returning to the heart is reduced, the blood pressure is lowered, and the uterine vein is bleeding, and the venous pressure is increased, causing blood stasis or rupture of the aponeuric vein bed, resulting in partial or total placenta from the uterine wall. Stripped.

an examination

1.B type ultrasound examination

A typical sonogram shows a liquid hypoechoic zone with an unclear edge between the placenta and the uterine wall, an abnormal thickening of the placenta or a "circular" split of the placenta edge. At the same time, the intrauterine condition of the fetus (with or without fetal movement and fetal heartbeat) can be seen, and the placenta previa can be excluded. It should be noted that negative results of ultrasound examination can not completely rule out placental abruption.

2. Laboratory examination

Includes complete blood count and coagulation function tests. Patients with grade II and III should be tested for renal function and carbon dioxide binding, and DIC screening tests should be performed, including platelet count, prothrombin time, and fibrinogen determination. Results Suspicious, further fibrinolysis diagnosis test, including thrombin time, euglobulin lysis time and plasma protamine paracoagulation test. Fibrinogen <250mg/L is abnormal, <150mg/L has diagnostic significance for coagulopathy. In case of emergency, 2 ml of blood of the elbow vein can be taken in a dry test tube, and the wall of the tube can be gently tapped. If no blood clot is formed or a fragile soft blood clot is formed after 7 minutes, it indicates coagulation dysfunction.

Differential diagnosis

It needs to be distinguished from the following symptoms:

Placenta retention in the uterine cavity: 30 minutes after the delivery of the fetus, the placenta has not yet been delivered, known as placental retention, is an important cause of postpartum hemorrhage. However, if the placenta is not completely stripped from the uterine wall, although the placenta is retained, there may be no bleeding for a period of time. Therefore, the correct treatment of placental retention is important for preventing postpartum hemorrhage and reducing maternal mortality.

Placenta preposition: The normal placenta is attached to the posterior wall, anterior wall or side wall of the uterus. If the placenta is attached to the lower part of the uterus, even if the lower edge of the placenta reaches or covers the inner opening of the cervix, its position is lower than the first exposed part of the fetus, called the placenta preposition.

Placental aging: Placental aging is the maturity of the placenta, which refers to the degree of aging of the placenta. The lower the degree of maturity, the better the function of the placenta, and the more nutrients it can provide for the baby.

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