Placental abruption

Introduction to placental abruption After 20 weeks of gestation or during childbirth, the placenta in the normal position is partially or completely detached from the uterine wall before delivery. This is called placentalabruption. Placental abruption is a serious complication of late pregnancy. Short course The onset is urgent and the progress is fast. If it is not handled 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. basic knowledge Proportion of the disease: the incidence rate of pregnant women is about 10% Susceptible population: pregnant women Mode of infection: non-infectious Complications: postpartum hemorrhage, disseminated intravascular coagulation, acute renal failure, amniotic fluid embolism, postpartum hemorrhage

Causes of placental abruption

High blood pressure (20%):

Hypertension includes pregnancy-induced hypertension syndrome (referred to as pregnancy-induced hypertension, especially severe pregnancy-induced hypertension), essential hypertension, chronic nephritis and hypertension, which are the primary causes of early exfoliation of the placenta. Some scholars have reported that pregnancy The early exfoliation of placenta in hypertensive patients is five times higher than that in normal blood pressure during pregnancy. The pathogenesis is mainly due to the occurrence of paralysis of the sacral sacral arterioles in the placenta attachment site, acute atherosclerosis, causing distal capillary ischemia and necrosis. , rupture and hemorrhage, the formation of hematoma, gradually enlarge, so that the placenta and the uterine wall are stripped and lead to early stripping of the placenta. If the pregnant woman has vascular disease such as essential hypertension and then complicated with pregnancy-induced hypertension, the vascular disease is aggravated, then the placenta occurs. There are more opportunities for early stripping.

Mechanical factors (15%):

The abdomen is directly impacted, often the cause of early dissection of the placenta, such as the impact of a car, sudden collision of the brakes when riding a bus, the first landing on the abdominal wall when the eye is falling, and the beating can cause the early dissection of the placenta, and the external reversal will be blocked when correcting the fetal position. If the placenta is located in the anterior wall of the uterus, amniocentesis may also cause early exfoliation of the placenta. Other indirect factors such as excessive amniotic fluid, sudden discharge of amniotic fluid when the embryonic membrane ruptures, or twin pregnancy The first fetus was delivered too fast, which caused the pressure in the uterus to drop suddenly, and the early exfoliation of the placenta occurred. The American study reported that the early exfoliation of the placenta caused by the trauma of pregnant women accounted for 1% to 2%.

Smoking (15%):

Nearly 10 years of research have confirmed the association between smoking and early exfoliation of the placenta. It has been reported that smoking increases the risk of early exfoliation of the placenta by 90%, and the risk of early exfoliation of the placenta increases with the increase in the number of cigarettes per day. Degenerative changes increase the fragility of capillaries, and the effect of nicotine on vasoconstriction and elevated concentrations of carbon monoxide-binding protein in serum can lead to vasospasm ischemia, which induces early exfoliation of the placenta.

Premature rupture of membranes (20%):

Many studies at home and abroad have reported the correlation between premature rupture of membranes and early exfoliation of placenta. The risk of early exfoliation of placenta in pregnant women with premature rupture of membranes is three times higher than that of premature rupture of membranes. The mechanism of its occurrence is not clear, and may be related to Premature rupture of membranes associated with chorioamnionitis.

1. Abuse of cocaine: It has been reported that 50 pregnant women were abused during pregnancy, 8 of them were due to early exfoliation of the placenta, and 112 pregnant women were reported to have abused cocaine during pregnancy, resulting in 13% of early placental ablation. .

2. Age and birth of pregnant women: The age of pregnant women is related to the early exfoliation of the placenta, but some scholars have reported that the number of births is more likely to be related to the early excision of the placenta than the age. The risk of early exfoliation of the placenta occurs with the increase of birth weight. Increased in geometric progression.

3. Others: The pregnant woman is in a supine or semi-recumbent position for a long time, so that the enlarged uterus compresses the inferior vena cava, obstructs the venous return, causing partial or complete placental dissection of the decidual venous congestion or rupture, and the umbilical cord is too short or the umbilical cord is around the neck. Around the body, during the delivery process, the first drop of the tire, the length of the umbilical cord is insufficient and pulled by force, can also lead to early stripping of the placenta.

Pathogenesis

The pathogenesis of early exfoliation of the placenta has not been fully elucidated. In the past, it was generally considered to be related to vascular disease, mechanical factors, sudden increase in uterine venous pressure and other factors.

The main pathological changes of the early placental exfoliation are hemorrhage of the decidua, which forms a hematoma, which causes the placenta to peel off from the attachment. If the area of the exfoliation is small, the blood will coagulate quickly after the bleeding stops. The clinical symptoms are asymptomatic, only the clots compress the placenta, in the placenta matrix. A trace of traces left on the surface is often found during postpartum examination of the placenta; if the area of the exfoliation is large, the hemorrhage after the placenta is continued to form, and the part of the placenta is continuously enlarged. At this time, the uterus cannot be contracted because the fetus has not been delivered, so it cannot stop bleeding. Function, bleeding continues to increase, can break through the edge of the placenta, along the fetal membrane and the uterine wall out through the cervical canal, that is, revealed abruption or external bleeding, if the edge of the placenta still adheres to the wall of the uterus, or The membrane is not separated from the uterine wall, or the fetal head is fixed at the entrance of the pelvis, so that the blood can not flow out after the placenta, the hematoma after the placenta is gradually enlarged, the placental exfoliation surface is also enlarged, and the fundus is continuously raised, which is recessive. Conealed abruption or internal bleeding, when the accumulation of hidden hemorrhage is too much, the blood can still rush out of the edge of the placenta and the membrane, and form a hybrid Blood (mixed hemorrhage), and sometimes bleeding can be bloody amniotic fluid into the amniotic fluid via amniotic membrane.

The early placenta of the recessive placenta, the blood can not flow out, the bleeding gradually increases and the hematoma after the placenta is formed. As the pressure increases, the blood is immersed in the myometrium, causing the separation of muscle fibers, breaking, denaturation, blood immersion and even the serosal layer, uterine surface. Purple freckle is present. In severe cases, the entire uterus is bronze, especially in the placenta. It is called uteroplacental apoplexy. At this time, the muscle fibers are impregnated with blood, the contractile force is weakened, and there may be bleeding after production. Sometimes the blood is still It can penetrate into the abdominal cavity, or infiltrate into the broad ligament, fallopian tube, etc.

Severe placental early dissection, especially in intrauterine cases, can cause coagulopathy, necrotic placental villi and decidua at the site of exfoliation, release a large amount of tissue thromboplastin into the maternal circulation, activate the coagulation system and cause DIC, lung, kidney and other dirty There may be microthrombus formation in the capillaries of the device, causing damage to organs, massive loss of coagulation factors such as platelets and fibrinogen, and finally activation of the fibrinolytic system, resulting in a large amount of fibrin degradation products (FDP), which in turn leads to fibrinolysis. , exacerbate coagulopathy.

Placental abruption prevention

Strengthen prenatal examination, actively prevent and treat pregnancy-induced hypertension; strengthen management of high-risk pregnancy such as hypertension, chronic nephritis; avoid supine position and abdominal trauma in late pregnancy; abnormal position correction when correcting fetal position, the operation must be gentle Avoid excessive intrauterine pressure when handling excessive amniotic fluid or twin births.

Placental abruption complications Complications postpartum hemorrhage diffuse intravascular coagulation acute renal failure amniotic fluid embolism postpartum hemorrhage

1, utero placenta apoplexy

After the placenta, the hematoma is formed, especially the recessive stripping, and the blood does not flow out of the uterus. Due to the increase of local pressure, the blood can penetrate into the myometrium, causing the muscle fibers to separate and break, and the blood can also infiltrate and the uterine serosa layer, so that the surface of the uterus is present. Purple freckle, especially in the placenta planting department, is called uteroplacental apoplexy. This phenomenon was discovered by Coelelaire in the early 20th century, so it is also called the Coelelaire uterus. The blood can still seep and the fallopian serosa. Or in the broad ligament, even the essence of the ovary, sometimes there is free blood in the peritoneum, may flow through the fallopian tube into the abdominal cavity, the incidence of utero-placental apoplexy is difficult to calculate accurately, because this performance can only be seen in cesarean section, thus The actual incidence should be higher than reported, uterine placental stroke rarely affects uterine contractions, resulting in severe postpartum hemorrhage is rare, so it is not an indication for hysterectomy.

2, fetal maternal bleeding

In traumatic placental abruption, fetal to maternal bleeding can occur, generally non-traumatic placental abruption, fetal to maternal bleeding is only 20%, the amount is less than 10ml; but severe trauma, 1992 Stettler reported that 8 cases of fetal maternal bleeding reached 80 ~ 100ml.

3. Disseminated intravascular coagulation (DIC)

Early dissection of placenta with coagulopathy is the most common cause of coagulopathy during pregnancy. Early exfoliation of severe placenta, especially intrauterine cases, is likely to occur with DIC and coagulopathy, and placenta and decidua are rich in tissue coagulation. The active enzyme, when the placenta is peeled off early, the procoagulant enters the maternal blood circulation through the damaged blood vessels, activates the coagulation system, and causes microthrombus formation in the capillaries of DIC, lung, kidney and other organs, causing organ damage, platelets and fibers. The coagulation factors such as proproteins are consumed in large quantities. Therefore, the longer the early exfoliation of the placenta, the more the procoagulant substances enter the maternal blood circulation, and the DIC continues to develop, that is, activates the fibrinolytic system, producing a large amount of fibrin degradation product (fibrin degradation product, FDP), due to the large consumption of coagulation factors, combined with FDP and anticoagulant effect, leading to and exacerbate coagulopathy, clinical manifestations of subcutaneous, submucosal or injection site bleeding, uterine bleeding does not coagulate or only soft clots, even hematuria , hemoptysis or hematemesis, the first Chinese Blood Coagulation Society in 1987 proposed DIC (Amendment) Laboratory tests with the following 3 or more abnormalities can be diagnosed as DIC1 platelets <100 × 109 / L or progressive decline; 2 fibrinogen <1.5g / L or progressive decline; 33P test positive or blood FDP > 20mg /L;4 prothrombin time (PT) shortened or prolonged by more than 3s, or dynamically changed, or activated partial thromboplastin time (PTT) shortened or prolonged by more than 10s; 5 euglobulin lysis time shortened, or plasmin Lowering, for early exfoliation of severe placenta, hemoglobin and red blood cell count are often reduced, PT, PTT prolonged, 3P positive, fibrinogen decreased, FDP increased, suggesting DIC, DIC occurs in 30% of cases sufficient for fetal death DIC without fetal distress is not common.

4, acute renal failure

Early exfoliation of severe placenta is caused by severe pregnancy-induced hypertension syndrome. In severe pregnancy-induced hypertension syndrome, systemic arterioles are paralyzed, and intrarenal arterioles are also paralyzed, causing tissue hypoxia, glomerular vascular endothelial cells to swell and increase in volume. Blocking blood flow; renal ischemia; plus excessive blood loss during early exfoliation of the placenta, longer shock time and DIC, etc., causing a sudden decrease in renal blood flow, and severe ischemic necrosis of the renal cortex or renal tubule Or due to a large amount of cellulose deposition in the small arteries of the ball, resulting in acute ischemic necrosis of the kidney, acute renal failure, clinical manifestations: 1 oliguria or no urine, oliguria (<400ml/24h =, No urine (<100ml/24h=, most patients have a daily urine output of 50-100ml during oliguria; 2 hyperkalemia (>7mmol/L), hyperkalemia is one of the causes of death in patients with oliguria; 3 nitrogen Blood, due to oliguria, the kidneys can not discharge urea nitrogen and creatinine, resulting in elevated blood urea nitrogen and creatinine; 4 metabolic acidosis, due to the accumulation of acidic metabolites in the body and the consumption of alkali reserves, blood pH decreased, Lead to intracellular Inhibiting activity and changes occurring intermediate metabolites increased metabolic acidosis.

5, amniotic fluid embolism

When the placenta is peeled off early, the uterine sinus of the dissected surface is open. If the hemorrhage after the placenta breaks through the amniotic membrane and the blood enters the amniotic fluid, the amniotic fluid can also flow back into the open uterine blood vessels into the maternal circulation, forming an embolism causing pulmonary embolism in the lungs. A series of amniotic fluid embolism symptoms, such as pulmonary hypertension, respiratory and circulatory failure, DIC, multiple organ injury, etc., occur more before the baby is delivered. If the rescue is not timely, it may endanger the patient's life.

6, postpartum hemorrhage

Postpartum uterine contraction and coagulation dysfunction can be post-production bleeding, clinical manifestations of a large number of vaginal bleeding after delivery of the placenta, the blood often does not coagulate, the examination found that the end of the palace is not clear, the outline of the uterus is not obvious, the patient's face is pale, expression is indifferent, Hemorrhagic shock symptoms such as cold sweat, increased pulse rate, and decreased blood pressure.

7, intrauterine death

When the placental exfoliation area reaches 1/3, the fetus may have intrauterine distress or even death; when the exfoliation area reaches 1/2, most of the fetuses die, even if the symptoms of early atypical placental exfoliation are lighter, the hazard to perinatal children is also great. Therefore, even if the clinical symptoms are not serious, and the early exfoliation of the placenta is suspicious, the intrauterine condition should be closely monitored and actively treated.

Symptoms of placental abruption Common symptoms Uterine tenderness Uterine hard as plate-like abdominal pain Vaginal bleeding placenta on the mother's face ... Coagulopathy dysfunction during pregnancy, persistent abdomen... Uterine bleeding, pale bleed, internal bleeding

Sher (1985) classification is widely used in foreign countries to divide the early placental dissection into I, II, III degrees, I degree: mild, postpartum hematoma diagnosis based on placenta; II degree: intermediate type, fetal heart rate changes and clinical symptoms; III degree: severe disease, fetal death, IIIa, no coagulation dysfunction, IIIb has coagulopathy, China's textbooks divide it into light, heavy type 2, light type is equivalent to SherI degree, heavy weight includes SherII, III degree.

The most common typical symptom of early exfoliation of the placenta is painful vaginal bleeding, but the symptoms and signs of early exfoliation of the placenta are large.

1, light

Mostly vaginal bleeding and mild abdominal pain, the placental stripping surface usually does not exceed 1/3 of the placenta, more common in the delivery period, the main symptoms are vaginal bleeding, the amount of bleeding is generally more, the color is dark red, may be associated with mild abdominal pain Or abdominal pain is not obvious, the signs of anemia are not significant. If it occurs during childbirth, the labor progresses faster. Abdominal examination: soft uterus, intermittent contractions, uterus size consistent with the number of weeks of pregnancy, clear fetal position, normal fetal heart rate, if If the amount of bleeding is too much, the fetal heart rate may change. The tenderness is not obvious or only mild local (placental abruption) tenderness. Postpartum examination of the placenta shows that there are clots and indentations on the maternal surface of the placenta, sometimes neither symptoms nor signs. Obviously, only when the placenta was examined after delivery, the placenta had a clot and an indentation on the maternal surface, and the placental abruption was found.

2, heavy

Internal hemorrhage and mixed hemorrhage, the placental stripping surface exceeds 1/3 of the placenta, and there is a large post-placental hematoma, more common in severe pregnancy-induced hypertension, the main symptoms are sudden persistent abdominal pain and/or backache, Low back pain, the degree is different depending on the size of the peeling surface and the amount of blood accumulated after the placenta. The more the blood is, the more severe the pain is. In severe cases, nausea, vomiting, and even pale, sweating, weak pulse and blood pressure drop may occur. No vaginal bleeding or only a small amount of vaginal bleeding, the degree of anemia is not consistent with the amount of external bleeding, abdominal examination: palpation of the uterus is as hard as a plate, tenderness, especially at the placenta attachment, if the placenta is attached to the posterior wall of the uterus, then Uterine tenderness is not obvious, the uterus is larger than the number of weeks of pregnancy, and with the increase of hematoma after the placenta, the fundus is increased, the tenderness is more obvious, occasionally contractions, the uterus is in a high-tension state, the interval can not be very It is easy to relax, so the fetal position is unclear. If the placental stripping surface exceeds 1/2 or more of the placenta, the fetus will die due to severe hypoxia, so the fetal heart of the severe patient has disappeared.

Placental abruption

Abdominal examination

Light weight: soft uterus, tenderness is not obvious or only mild localized tenderness (placental abruption), its size is consistent with the month of pregnancy, fetal position, fetal heart sound is clear, but if the amount of bleeding is more, the fetal heart rate may have Change, end of delivery in a short time, postpartum examination of the placenta, visible clots and pressure marks on the placenta.

Heavy: The uterus palpation is as hard as a plate, with tenderness, especially at the placenta attachment. However, if the placenta is attached to the posterior wall of the uterus, the uterus is less compressed, the uterus is larger than the pregnancy month, and as the disease progresses, After the placenta, the hematoma continues to increase, and the fundus is also increased accordingly. The tenderness is also more obvious. Occasionally, the uterus shrinks, but the uterus can not relax very well in the intermittent period, but the position is high, so the fetal position is unclear. The placenta peeling surface is more than 1/2, and the fetus is often killed by severe intrauterine distress.

Ultrasonography

Severe placental abruption can be diagnosed according to clinical examination. For clinical manifestations are not serious, the examination can not be confirmed, can be used for ultrasound examination, ultrasound images can have the following performance: 1 postpartum hematoma, appearance between the placenta base plate and the uterine wall Regular liquid hemorrhagic dark areas and convex to the placenta, in sharp contrast with the parenchymal echo of the placenta, 2 placenta thicker than normal, 3 choriocalulus hematoma, when the decidual vascular rupture, blood flow along the placenta leaflet to the placenta When the child is decent, a hematoma is formed under the chorion plate. The ultrasound image is a gas-like dark area, which separates the placenta from the chorion and protrudes into the amniotic cavity. When the posterior wall of the posterior wall is stripped early, the fetus is closer to the anterior wall of the uterus. 5, abnormal echo in amniotic fluid, such as blood infiltrated into the amniotic membrane along the edge of the placenta, can make amniotic fluid into blood, ultrasound shows a flow of point echo in the amniotic fluid, echo distribution is sparse, mostly concentrated near the lesion, such as early placenta Peeling, the blood flows out along the cervical canal, does not form a hematoma after the placenta, without the above ultrasound image, so B-mode ultrasound diagnosis has certain limitations, heavy The early exfoliation of the placenta is often accompanied by fetal heart, and the fetal movement disappears.

Laboratory test

Mainly through blood routine examination to understand the degree of anemia, coagulation function test, do DIC screening test (platelet count, prothrombin time, fibrinogen determination), and fibrinolysis diagnosis test (thrombin time, proteolytic time, plasma fish Protamine secondary coagulation test), blood routine, platelet, clotting time and fibrinogen and other related DIC tests; urine routine, in patients with severe placental abruption, urine protein is often (+), (++) or more For emergency patients, the fibrinogen content can be estimated by a simple and convenient whole blood clot observation and dissolution test to diagnose early coagulopathy.

Diagnosis of placental abruption

diagnosis

1, diagnosis basis

(1) may have a history of trauma, history of vascular disease.

(2) There is vaginal bleeding accompanied by abdominal pain.

(3) The uterus has limited tenderness and tenderness, and it is in a hypertonic state, and the fundus is elevated.

(4) The fetal heart is weakened or even disappeared.

(5) Ultrasound examination showed a dark area between the uterine wall and the placenta. The echo in the amniotic fluid increased and the villus board protruded into the amniotic cavity.

(6) Blood protein is reduced, and coagulation dysfunction may occur.

(7) postpartum examination of the placenta can be seen on the maternal surface of the placenta with clots and pressure marks.

2, classification diagnosis

(1) Light placental abruption: the placental stripping surface usually does not exceed 1/3 of the placenta area, manifested as vaginal bleeding, anemia signs are not significant, mild abdominal pain or no abdominal pain, intermittent contractions, clear fetal position, fetal heart rate More normal, sometimes symptoms and signs are not obvious, only found in the placenta maternal surface clots and pressure marks.

(2) severe placental abruption: the placental stripping surface exceeds 1/3 of the placenta area, showing abdominal pain is severe and continuous, no vaginal bleeding or a small amount of vaginal bleeding, the degree of anemia is not consistent with external bleeding, the uterus is as hard as a plate, tenderness, There is no contraction, the fetal position is unclear, the sheep is bloody, and the fetal heart can disappear when the condition is serious.

3, must pay attention to the cause of the disease

Those with pregnancy-induced hypertension, especially those with moderate or severe pregnancy-induced hypertension, are prone to early exfoliation of the placenta. There are reports that 40.5% of the early placenta dips and pregnancy-induced hypertension, and 14.8% of those with trauma, the author believes that pregnancy-induced hypertension Patients with fetal growth restriction and anemia are more likely to have early placental ablation, which should be noted.

4. Comprehensive analysis based on clinical symptoms and signs

Most cases of early exfoliation of light placenta may start with a small amount of painless vaginal bleeding, and then develop into painful vaginal bleeding. Therefore, combined with medical history, the nature of vaginal bleeding and contractions should be closely observed, fetal heart changes, combined with auxiliary examination. Early diagnosis and treatment, severe early placental symptoms and signs of severe placenta are more typical, no more difficult to diagnose, but should be judged the severity, when the uterine bleeding is not only, the skin and mucous membranes have bleeding, which often indicates the presence of DIC, should be particularly vigilant.

5, the placenta attached to the posterior wall of the uterus early stripping of the placenta

This is most easily overlooked, especially in the early days, which is characterized by the fact that in the third trimester of pregnancy, with or without vaginal bleeding, as long as the uterus tension is unknown, but not too much amniotic fluid, and not in labor, it is not high. Tension uterine contractions, especially those with pregnancy-induced hypertension associated with fetal growth restriction, although the fetal heart is still normal, the possibility of early placental exfoliation of the placenta attached to the posterior wall of the uterus must be considered, and B-mode ultrasound can be used to detect fetal heart rate. Monitoring to assist with diagnosis.

Differential diagnosis

In late pregnancy, in addition to placental abruption, there are still placenta previa, uterine rupture and bleeding of cervical lesions, etc., should be identified, especially in the identification of placenta previa and uterine rupture.

1, placenta previa

Light placenta premature detachment, can also be painless vaginal bleeding, signs are not obvious, B-mode ultrasound examination to determine the lower edge of the placenta, can be diagnosed, placental abruption of the posterior wall of the uterus, abdominal signs are not obvious, difficult to place with placenta The difference, B-ultrasound can also be identified, the clinical manifestations of severe placental abruption are very typical, it is not difficult to distinguish with the placenta previa.

2, the uterus rupture

Often occurs during childbirth, strong contractions, lower abdominal pain refused to press, irritability, a small amount of vaginal bleeding, fetal distress signs, etc., the above clinical manifestations and heavy placental abruption are difficult to distinguish, but the aura of uterus rupture more than the head basin Not to mention, childbirth obstruction or cesarean section history, examination can be found in the uterus pathological ring, catheterization, gross hematuria, etc., and placental abruption is often a patient with severe pregnancy-induced hypertension, check the uterus is plate-like hard.

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