DefinitionPlasenta abruption is separation from its implantation site before delivery and in Great Britain, accidental hemorrhage. The Latin term abruptio placentae means rending asunder of the placenta and denotes a sudden accident, which is a clinical characteristic of most cases. The cumbersome term premature separation of the normally implanted placenta is most descriptive.

The bleeding of placental abruption typically insinuates itself between the membranes and uterus, ultimately escaping through the cervix, causing external hemorrhage. Less often, the blood does not escape externally but is retained between the detached placenta and the uterus, leading to concealed hemorrhagePlacental abruption may be total or partial. Concealed hemorrhage carries much greater maternal and fetal hazards. This is not only because of possible consumptive coagulopathy, but also because the extent of the hemorrhage is not readily appreciated, and the diagnosis typically is delayed

Hemorrhage from extensive placental abruption. External hemorrhage: the placenta has detached peripherally, and the membranes between the placenta and cervical canal are detached from the underlying decidua. This allows blood egress through the vagina. Concealed hemorrhage: the periphery of the placenta and the membranes are still adhered and blood remains within the uterus. Partial placenta previa: there is placental separation and external hemorrhage.

EpidemiologyAbruption severity often depends on how quickly the woman is seen following symptom onset. With delay, the likelihood of extensive separation causing fetal death is increased remarkably.The frequency with which placental abruption is diagnosed varies because of different criteria, but reported frequency averages 1 in 200 deliveries.

EpidemiologyNational Center for Health Statistics ~ incidence in singleton births of 1 in 160. Birth certificate data for the US for 2003 ~ incidence of placenta abruption was found to be 1 in 190 deliveries. Parkland Hospital from 1988 - 2006 ~ incidence of placenta abruption in more than 280,000 deliveries has been approximately 1 in 290.

EpidemiologyBoth incidence and severity have decreased over timeAs the number of high parity women giving birth decreased and as availability of prenatal care and emergency transportation improved, the frequency of abruption causing fetal death dropped to approximately 1 in 830 delivery from 1974-1989. Between 1996-2003, it decreased further to approximately 1 in 1600.

Perinatal Morbidity and Mortality(Salihu and colleagues) in the US between 1995-1998 ~ the perinatal mortality rate associated with placental abruption was 119 per 1000 births compared with 8 per 1000 for those without this complication.The high perinatal mortality rate ~ increased incidence of preterm delivery and fetal-growth restriction. There are also increased serious adverse sequele in infants who survive (neurological deficits).

EtiologyMany cases continue to be idiopathic, but placental abruptio is associated with maternal hypertension, advanced maternal age, multiparity, cocaine use, tobacco use, chorioamnionitis, and trauma.Patients with chronic hypertension, superimposed pre-eclampsia, or severe pre-eclampsia have a fivefold increased risk of severe abruption compared to normotensive counterparts. Moreover, antihypertensive medications have not been shown to reduce the risk of abruption in patients with chronic hypertensionIn patients who smoke, the risk of a stillbirth resulting from placental abruption is increased 2.5-fold and increases 40% for each pack per day smoked

Etiology4.Rarely, rapid contraction of an overdistended uterus may lead to abruption, such as with rupture of membranes with polyhydramnios, or delivery of an infant in a multiple gestation.5.Abruptions also occur more frequently when the placenta implants over a uterine anomaly or myoma.6.Inherited thrombophilias, such as hyperhomocysteinemia, Factor V Leiden and prothrombin 20210 mutations are associated with an increased risk of abruption

Clinical ManifestationThe amount of external bleeding varies from none to massive hemorrhage. The amount of bleeding, however, does not correlate well with the severity of the abruptionThe presence of blood in the basalis stimulates uterine contractions, which results in abdominal pain.Fetal and maternal mortality rates vary, depending on the location and size of the hemorrhage.

PathophisiologyPlacental abruption is initiated by hemorrhage into the decidua basalis. The decidua then splits, leaving a thin layer adhered to the myometrium. Consequently, the process in its earliest stages consists of the development of a decidual hematoma that leads to separation, compression, and ultimate destruction of the placenta adjacent to it. There is histological evidence of inflammation more commonly in cases of placental abruption than in normal controls. inflammationinfectionmay be a contributor to causal pathways.

In its early stage, there may be no clinical symptoms, and the separation is discovered upon examination of the freshly delivered placenta. In these cases, there is a circumscribed depression on the placentas maternal surface. It usually measures a few centimeters in diameter and is covered by dark, clotted blood. Because several minutes are required for these anatomical changes to materialize, a very recently separated placenta may appear to be totally normal at delivery.

Substantive-sized dark clot is well formed, it has depressed the placental bulk, and it likely is several hours old. In some instances, a decidual spiral artery ruptures to cause a retroplacental hematoma, which as it expands, disrupts more vessels to separate more placenta. The area of separation rapidly becomes more extensive and reaches the margin of the placenta. Because the uterus is still distended by the products of conception, it is unable to contract sufficiently to compress the torn vessels that supply the placental site. The escaping blood may dissect the membranes from the uterine wall and eventually appear externally or may be completely retained within the uterus2

Diagnosis Clinical ~ vaginal bleeding, uterine tenderness or back pain, fetal distress (CTG) , uterine contractions and persistent uterine hypertonus. Pain from abruption may mimic normal labor or it may be painless, especially with posterior placenta. At times, the cause of vaginal bleeding remains obscure even after delivery.Sonography : sonography infrequenly confirms the diagnosis of placental abruption at least acutely, because the placenta and fresh clot have similar sonographic appearance. (Negative findings with sonographic examination do not exclude placental abruption)

DiagnosisNeither laboratory tests nor diagnostic methods are available to detect lesser degrees of placental separation accurately. It often becomes necessary to exclude placenta previa and other causes of bleeding by clinical and sonographic evaluation.Clinically, painful uterine bleeding signifies placental abruption, whereas painless uterine bleeding is indicative of placenta previa.

Diagnosis(after delivery)Retroplacenta hematomeCouvelaire uterus from total placental abruption after cesarean delivery. Blood markedly infiltrates the myometrium to reach the serosa, especially at the cornua. It gives the myometrium a bluish-purple tone as shown

ManagementBased on maternal and fetal condition, gestational age and severityFluid Rescucitation and Blood transfusion hypovolemic shock and consumptive coagulopathyContinuous monitoring of fetal heart rate and maternal laboratory assessmentPreterm pregnancyExpectant management in preterm pregnancy and Tocolysis Close observation of fetal conditionFetal corticosteroid prepare terminationTerm or near term pregnancyTermination:Sectio Caesarian preferred in emergency settingOxytocin for vaginal delivery

PrognosisNeonatal outcome:10 times risk of perinatal deathGreater risks for adverse long-term neurobehavioral outcomesRisk for periventricular leukomalacia and sudden infant death syndrome

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