What are classical signs indicating that the placenta has separated from the uterus?

Pregnancy: Pre-eclampsia and Diet

E. Abalos, in Encyclopedia of Human Nutrition (Third Edition), 2013

Glossary

Abruptio placentae

Abnormal separation of the placental lining from the uterus occurring after 20 weeks of gestation and prior to birth.

Confidence interval

A particular kind of interval estimate of a population parameter used to indicate the reliability of an estimate.

Eclampsia

Acute and life-threatening complication of pregnancy characterized by the appearance of tonic-clonic seizures in a patient who had developed pre-eclampsia.

Ischemia

Restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue.

Relative risk

A ratio of the probability of the event occurring in the exposed group versus a non-exposed group.

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Medical Care

Mahoney James, in The Laboratory Primate, 2005

Uterine hemorrhage

Placenta abruptio (premature separation of the placenta) and placenta praevia (implantation of the placenta low in the uterine segment or over the internal os of the cervix) account for approximately 2% of pregnancy-related emergencies in macaques (Mahoney et al., 1979) and other species.

Second stage labor in nonhuman primates is usually not marked by significant blood loss. In fact, vaginal bleeding may not even be seen before the birth of the infant. Heavy vaginal hemorrhage, especially of sudden onset, is therefore an ominous sign and its cause must be immediately investigated. Not only may the life of the infant be threatened but also that of the dam.

Surgical intervention (hysterotomy), with careful haste, is the order of the day if there is to be any hope of saving not only the fetus but also the mother. The mother, if she survives the acute hemorrhage, will almost certainly require emergency blood transfusion with typed and cross-matched blood. Under no circumstances should labor be induced by giving IM boluses of oxytocin, because this risks causing uterine rupture and fatal crushing of the fetal head during the ensuing uterine spasm.

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Urogenital System

J. Mark Cline, ... Elizabeth W. Ford, in Nonhuman Primates in Biomedical Research (Second Edition), Volume 2, 2012

Placenta Abruptio

Placenta abruptio refers to premature separation of the normally implanted placenta prior to the birth of the fetus (Scott, 1999). Etiological factors, such as short umbilical cord, uterine anomalies, trauma, and hypertension, may be responsible; however, the cause is obscure in most animals. The separation most often takes place in the third trimester, but can happen at any time. Frequently the placental separation is an acute process that increases in severity over a few hours. At other times, the episode varies from a self-limited one to one that becomes quiescent and then recurs. The placental separation may be complete, partial, or involve only the placental margin (Figure 10.21).

Separation of the placenta is initiated by bleeding into the decidua basalis. The bleeding splits the decidua and spreads beneath the placenta, shearing it off. As a hematoma forms, it causes additional separation of the placenta from the uterine wall with destruction and compression of adjacent placental tissue. Occasionally, blood extravasates into and through the myometrium to the peritoneal surface, giving the uterus a bluish color. The effects on the fetus depend mainly on the degree of disruption at the uteroplacental interface (Figure 10.22).

What are classical signs indicating that the placenta has separated from the uterus?

FIGURE 10.22. Placenta abruptio may present as acute, asymptomatic death of a pregnant female when the hemorrhage is concealed, or as profuse life-threatening vaginal hemorrhage.

(A and B) Both resulted in maternal and fetal death. In both instances the blood loss occurred retroplacentally with no external hemorrhage (A) to a few drops (B). (C) Blood extravasated through the myometrium giving a blue color to the uterus. Bleeding was also concealed in this case. (D) Sonograph of a second-trimester pregnant uterus indicating the marginal separation of the placenta. Careful monitoring of this animal resulted in no further evidence of separation and subsequent normal delivery of a healthy infant.

The diagnosis of placental abruption is based on clinical signs and ultrasound monitoring. Abdominal pain, pallor, uterine contractions, and uterine tenderness are primary clinical signs. Hemorrhage, however, may be visible, partially visible, or concealed. Hemorrhage may extravasate into the myometrium, into the amniotic fluid, or behind the placenta (Figure 10.21). A concealed abruption, which can be identified with ultrasound, must be differentiated from premature labor, uterine rupture, and severe preeclampsia. Visible hemorrhage during the second or third trimester must be differentiated from impending abortion, placenta previa, vaginal or cervical lacerations or polyps, cervical carcinoma, and ruptured uterus.

Placenta abruptio has been described in Macaca mulatta (Myers, 1972), M. fascicularis, and Saimiri sciureus (Cukierski et al., 1985). Of the 21 cases in the latter review, 24% resulted in death of the dam and fetus and 52% in death of the fetus only. Approximately 75% had a history of abnormal vaginal bleeding during pregnancy and 19% had concealed hemorrhage. Clinical signs were varied and included depression, pallor, little or no vaginal bleeding, and a painful abdomen. Fetal heart beats were slow and irregular, indicating distress. Of the predisposing factors, the most obvious were a thickened proliferative decidua (33%) and a history of abortions and/or abruptions (29%). Sequelae included endometritis, hypovolemic shock, disseminated intravascular coagulation, and death (Cukierski et al., 1985).

A 12-year-old multiparous lion-tailed macaque (Macaca silensis) suddenly became ataxic (Calle and Ensley, 1985). Physical examination revealed hypothermia, mucous membrane pallor, and a near-term fetus. The fetus was removed by hysterotomy after ultrasonic examination of the abdomen indicated its death. At the time of surgery, one-half to two-thirds of the placenta had separated from the uterus and the intervening space was occupied by a 10-cm fresh blood clot and approximately 75 ml of nonclotted blood.

Management depends on the stage of gestation and the condition of the dam and fetus. Marginal or mild degrees of premature separation can be monitored closely with frequent ultrasound examinations but no immediate intervention. Although external bleeding is typically moderate in amount, the total blood loss may be much greater. Additionally, the onset of symptoms may be gradual or abrupt with continuously progressing hemorrhage and contraction of the uterus. Greater degrees of abruption or progression require a more aggressive approach, involving stabilization of the dam and immediate surgical delivery of the fetus and placenta. Fetal distress is common. Placenta abruptio may also cause fetal brain damage secondary to hypoxia (Myers and Brann, 1976). Maternal hypotension, tachycardia, hypothermia, and oliguria indicate shock and should be aggressively managed with fluid therapy and whole blood transfusion. Postsurgically, the dam should be monitored for uterine involution, coagulopathy, and hypovolemic shock.

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Complications of Pregnancy

Richard Beukema MD, ... Barbara F. Kelly MD, in Family Medicine Obstetrics (Third Edition), 2008

B. Abruptio Placenta

Abruptio placenta occurs when there has been a premature separation, either partial or complete, of the placenta from the uterine wall.

1.

Incidence

Uterine abruptio occurs in 0.5% to 1.1% of all pregnancies,17 with approximately 0.2% severe enough to result in fetal death.

2.

Clinical presentation

The presentation of this disorder is extremely variable, with hemorrhage, bloody amniotic fluid, or concealed hemorrhage being possible. A placental abruption often presents with pain in the abdomen or back. Abruptions are commonly graded on a scale of 1 to 3 based on amount of bleeding (often diagnosable only after delivery), degree of uterine irritability, and fetal well-being. Grade 1 abruptions have little bleeding, slight irritability, and reassuring fetal heart tracings. Grade 2 abruptions have moderate bleeding, have irritable to tetanic uterine activity, and show evidence of fetal compromise. Grade 3 abruptions are characterized by severe bleeding, painful and tetanic uterine activity, and fetal death. The relative percentage of each of these is 40%, 45%, and 15%, respectively.17 The clinical presentation is discussed further in Chapter 16, Section D.

3.

Risk factors

Risk factors are additive. Hypertensive disorders are the most common risk factor, being present in 36% to 59% of all patients with severe abruptio.18 Uterine anomalies and leiomyomata were uncommon causes of abruptio in one large series,18 implying less risk than previously suggested with leiomyomata.2,19

Many forms of substance abuse, especially tobacco (RR, 2.46), alcohol, and cocaine, are associated with an increased risk for abruptio placentae. Other conditions associated with abruptio include20:

a.

Sudden decompression of an overdistended uterus (ruptured membranes in polyhydramnios)

b.

Chronic hypertension and preeclampsia (RR, 4.39)

c.

Blunt abdominal trauma (see Chapter 9, Section C)

d.

Grand multiparity (RR, 3.60)

e.

History of previous abruptio placenta (RR, 4.50)21

f.

Velamentous cord insertion (RR, 2.53)

g.

Advanced maternal age (RR, 1.62)

h.

Previous CS (RR, 1.7)21

It is important to keep in mind, however, that most cases of abruption occur in low-risk pregnancies and are not predictable.20

4.

Diagnosis

The diagnosis of abruptio may be made on ultrasound, but diagnostic priority should be given to clinical features. A negative ultrasound scan does not eliminate the diagnosis of abruptio.

5.

Complications

Complication rates of abruption are common and increase if the fetus is stillborn at admission. The following complications are most frequent. Complication rates are listed as those for viable versus stillborn fetus at admission.22

a.

Bleeding severe enough to require transfusion: 30.1% versus 63.3%

b.

DIC: 7.2% versus 28.3%

c.

Acute renal failure: 2.0% versus 5.0%

d.

Acute respiratory distress syndrome: 2.0% versus 5.0%

e.

Composite: 11.3% versus 68.3%

6.

Strategies for antepartum management

a.

Second-trimester abruptions have been thought to carry a poor prognosis for the pregnancy. Studies suggest that partial abruption in a severely preterm fetus may be managed conservatively if maternal and fetal parameters are stable.3,9,23 Preterm patients who are stable should be considered for transfer to a tertiary facility.

b.

The value of Doppler testing in the management of abruptio has not been demonstrated,20,21,24 except in the case of accompanying IUGR. Antepartum assessment otherwise consists of NST and serial sonographic examination for fetal growth.23,25

c.

Although previously considered controversial, tocolysis appears to be safe and helpful in delaying preterm birth and its associated morbidity in patients with partial abruptio and significantly preterm fetuses.3,7,9,23 Magnesium sulfate appears to be preferable to β-sympathomimetics and nifedipine because of their hemodynamic effects. Indomethacin is contraindicated because of its effect on clotting.

d.

It should be remembered that all Rh-negative patients with significant antenatal bleeding should receive 300 mg Rh-immunoglobulin (RhoGAM). If a larger fetomaternal bleed is suspected, a Kleihauer–Betke test may be performed to determine the number of units of RhoGAM indicated.

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Maternal Age and Pregnancy

R.C. Fretts, ... L.J. Heffner, in Encyclopedia of Infant and Early Childhood Development, 2008

Abnormal Placentation

Placental abnormalities include placenta abruption and placental previa. Placental abruption, in which the placenta separates from the wall of the uterus prematurely and both fetal and maternal hemorrhage can occur, is a serious complication of pregnancy and can lead to both fetal and maternal death. Placenta previa, or placenta covering the cervix, which predisposes to hemorrhage as cervical dilation occurs, also represents a serious concern. Both of these conditions do occur more commonly in older women, although a large portion of this additional risk is associated with increasing parity. Nonetheless, Gilbert et al. found a 10-fold increased risk of placenta previa in women 40 years of age having their first birth when compared to women ages 20–29 years, although the absolute risk of this was small (0.25% vs. 0.03%). The increased risk of abruption may be somewhat explained by the increased frequency of hypertensive disorders of pregnancy in older women.

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Gynecological and Obstetric Emergencies

Steven W. Salyer PA‐C, ... Katherine Anne Harrison, in Essential Emergency Medicine, 2007

Etiology

The primary etiology of abruptio placentae is unknown, but multiple risk factors have been associated with abruptio placentae. Risk factors include the following:

Maternal hypertension: most common cause of abruption (40%–50% are associated with hypertensive disease of pregnancy)

Maternal trauma (e.g., motor vehicle accidents, assaults, falls)

Cocaine use

Sudden decompression of the uterus (e.g., premature rupture of membranes, delivery of first twin)

Multiple gestations/maternal age/grand multiparity

Previous abruption: risk of recurrence ranges from 5.5% to 16%

Inherited thrombophilia

Retroplacental myoma

Idiopathic factors: probable abnormalities of uterine blood vessels and decidua

Cigarette smoking

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Gestational Diseases and the Placenta

Emily E. Meserve, ... Theonia K. Boyd, in Diagnostic Gynecologic and Obstetric Pathology (Third Edition), 2018

Placental Abruption/Abruptio Placentae

Historical/Clinical Background

The placental pathology of abruption placentae is discussed in Chapters 31 and 32, the latter within the “Acute Catastrophic Demise” section. Caveat: The causes of induced delivery in the setting of maternal bleeding will naturally overlap with those of spontaneous antepartum hemorrhage.

Clinical Evaluation

The two main differential considerations of antepartum hemorrhage are (1) abruptio placentae and (2) placenta previa. An abruptio placentae, or premature placental separation, is manifested by significant vaginal bleeding in the late second to third trimesters. However, abruption can also be clinically silent, and patients may present without vaginal bleeding (although abdominal pain and rigidity may still be present). So-called concealed abruption may occur in as many as 20% of cases clinically classified as abruption following fetal and placental delivery. Bleeding because of placental abruption is not typicallylife threatening to the mother but may threaten thefetus, resulting in stillbirth about 35% of the time. Fetal distress, which may eventuate in chronic morbidity or mortality, is due to hypoxia secondary to maternal and sometimes fetal hemorrhage; susceptibility for untoward outcome appears enhanced in the setting of concealed abruption. Other clinical manifestations of abruption include premature labor, labor with hypertonic uterine contractions, “port wine” amniotic fluid noted at cesarean section, and large clots passed with the placenta followingvaginal delivery. There are multiple predisposing factors associated with placental abruption, and patients may present with clinical features of preeclampsia, gestational or chronic hypertension, or uterine over-distention (multiple pregnancy or polyhydramnios) or history of cocaine abuse or maternal abdominal trauma (e.g., unexpected falls, motor vehicle accidents). Multiple predisposing factors associated with placental abruption include maternal hypertension, preeclampsia, uterine over-distention (multiple pregnancy or polyhydramnios), cocaine abuse, and maternal abdominal trauma (e.g., unexpected falls, motor vehicle accidents).

Clinical Correlates/Outcomes

Although uncommon, placental abruption remains a significant cause of maternal and morbidity andperinatal mortality. Maternal complications are primarily related to blood loss, including long-term risk ofcardiac disease,78 whereas fetal complications are related to hypoxia due to placental malperfusion. The natureof risk or complication to the mother depends on the severity of the bleeding and to the fetus on theseverity of the bleeding compounded by gestational age. Bleeding because of placental abruption is not typically lifethreatening to the mother but is associated with the need for blood transfusion, emergency hysterectomy, disseminated intravascular coagulopathy, and renal failure. Fetal complications include stillbirth; and in live births low birth weight, preterm delivery, and features of neonatal asphyxia.79-81

Differential Diagnosis and Potential Pitfalls

In the setting of antepartum hemorrhage, the main clinical differential diagnosis is placenta previa. This differential diagnosis can typically be resolved by imaging studies. If gross examination is performed, features that support the diagnosis of placenta previa include point of membrane rupture that reaches the edge of placental disc and marginal and velamentous umbilical cord insertions; however, these features are not specific. Furthermore, cases of both placenta previa and placenta abruption may exhibit maternal surface disruption, and both placenta previa and chronic abruption may exhibit marginal retroplacental blood clots.

Based on gross examination finding of adherent blood clot, the pathologic differential diagnosis includes inflammatory abruption and chronic abruption. The gross and microscopic features distinguishing these entities have been previously discussed.

Key Clinicopathologic Questions Faced by the Pathologist

Q: What if there is a clinical diagnosis of abruption but the pathologic features (retroplacental bleeding with overlying placental infarction) are not fully present?

A: In this case, a comment can be made: “Diagnostic features of placental abruption are not present. However, abruption occurring shortly before delivery may not manifest diagnostic pathologic changes.”

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TRANSFUSION MEDICINE

Barbara Alving, in Blood Banking and Transfusion Medicine (Second Edition), 2007

Obstetrical Conditions

Disseminated intravascular coagulation can occur with abruptio placentae, amniotic fluid embolism, retained placenta, preeclampsia, acute fatty liver, and in utero fetal death.55 These processes are all associated with the release of tissue factor from the dead fetus or necrotic placenta. DIC is clinically noted by excessive or spontaneous bleeding combined with decreases in fibrinogen levels and platelet counts and increases in D-dimer.

The best treatment is to accomplish delivery as soon as possible. Blood products are given as needed until this can be achieved. The contraction of the myometrium and removal of the source of tissue factor are the two most important factors in controlling the DIC.55 With proper treatment, the coagulopathy reverses in hours and no further treatment is required. The only obstetrical condition associated with DIC for which heparin has been efficacious is the rare condition in which fetal death has occurred in one of two or more fetuses carried by the mother. Full-dose intravenous heparin has been administered to allow the maturation and delivery of the other viable fetuses.56,57

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Trauma in the Pregnant Patient

Julie Grimes MD, Frances Rosenbaum MD, in Parkland Trauma Handbook (Third Edition), 2009

VI. Obstetric Emergencies in the Trauma Patient

The following is a brief list of complications unique to the pregnant trauma patient that should be considered at the time of the secondary survey. The help of obstetricians is required in the diagnosis and management of each.

A.

Traumatic placental abruption

1.

Abruptio placentae, or premature separation of the normally implanted placenta, complicates 1% to 6% of minor injuries and up to 50% of major injuries.

a.

This should be high on the list of differential diagnoses when the injured gravid patient presents with shock, disseminated intravascular coagulation, uterine tenderness, vaginal bleeding, ruptured fetal membranes, fetal jeopardy, or fetal death.

2.

In some cases of abruption, there may be no vaginal bleeding or other physical findings and the abruption may be confused with labor.

3.

Fetal electronic monitoring is the most sensitive method for detecting abruption and subtle signs of fetal jeopardy.

a.

Monitoring should begin as soon as possible after maternal stabilization in women whose fetuses are 20 to 22 weeks estimated gestational age (EGA).

b.

Women are typically monitored for a minimum of 4 hours.

c.

Contractions or nonreassuring fetal heart rate tracings warrant an extended monitoring period of at least 24 hours.

4.

Blood for laboratory tests (CBC, PT/PTT, d-dimers, Kleihauer-Betke stain, fibrinogen, group and screen, and a thrombin clot tube) should be drawn while the patient is in the trauma bay.

5.

Placental abruption is one of the most common causes of obstetric consumptive coagulopathy.

a.

Blood loss accompanied by hypofibrinogenemia may be substantial.

6.

In the setting of placental abruption with a live fetus of viable gestational age, the decision to deliver the fetus and the mode of delivery must be made by experienced obstetricians after stabilization of the mother.

7.

In Rh-negative women with evidence of fetomaternal hemorrhage, anti-D immunoglobulin (Rhogam) must be given to prevent Rh isoimmunization.

B.

Uterine rupture

1.

This uncommon event occurs in fewer than 1% of blunt trauma patients.

a.

This must be considered if the patient has suffered direct and intense force to the abdomen/uterus.

2.

When uterine ruputure occurs, rapid deterioration of the mother and the fetus is likely.

3.

The diagnosis of uterine rupture may be suspected by history, physical examination, or radiologic studies, but often the diagnosis is not confirmed until celiotomy.

4.

Repair of the uterus is possible, but emergency hysterectomy is often required.

C.

Fetal injury/fetal jeopardy

1.

The risk of fetal injury is high when factors such as hypoxia, head injury, pelvic fracture, placental injury, and shock are present in the mother.

2.

Direct fetal injury occurs two thirds of the time when the uterus sustains penetrating trauma.

a.

Fetal skull and brain injuries are especially common with pelvic fractures in gravid women when the fetal head is presenting and engaged in the pelvis.

3.

Fetal jeopardy in a viable fetus can be diagnosed with electronic monitoring and an experienced obstetrician.

a.

If the mother has been adequately stabilized, emergency cesarean section may be considered

D.

Umbilical cord prolapse

1.

Spontaneous rupture of fetal membranes has been seen both with and without contractions after blunt trauma.

2.

If the presenting fetal part is not well engaged in the maternal pelvis, the fetal umbilical cord may prolapse into the vagina.

3.

Cord prolapse requires emergent cesarean delivery in a viable fetus, as fetal hypoxia and death will quickly ensue.

E.

Impending maternal death

1.

In the case of a dead or moribund pregnant patient, the decision to perform emergency cesarean delivery must be made quickly, as fetal survival is unlikely if more than 20 minutes have elapsed since the death of the mother.

2.

There is an inverse correlation between neurologically intact neonatal survival and the cardiac-arrest-to-delivery interval in women delivered by perimortem cesarean.

3.

During cardiopulmonary resuscitation, left lateral uterine displacement is essential for adequate cardiac output in a gravid female.

4.

Consideration is given to fetal age and fetal condition (presence and rate of fetal heart tones).

5.

The senior pediatrician, his or her resuscitation team, and, if possible, the neonatologist should be present at delivery.

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Antepartum Hemorrhage

Lawrence C. Tsen, in Complications in Anesthesia (Second Edition), 2007

PLACENTAL ABRUPTION

Placental abruption—also referred to as abruptio placentae or placental separation—is defined as the premature separation of a normally situated placenta from its attachment to the placental decidua basalis before the birth of the fetus. Such separation is thought to result from a rupture of placental arteries or veins. In 20% to 35% of cases, the bleeding site is “concealed”; that is, there is no obvious vaginal bleeding. Placental abruption occurs in 0.5% to 1.8% of all pregnancies, with approximately 40% of cases occurring after the 37th week of gestation, 40% occurring between the 34th and 37th weeks, and less than 20% occurring before the 32nd week.

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What are the signs of separation of placenta?

In some cases, placental abruption develops slowly (chronic abruption), which can cause light, intermittent vaginal bleeding..
Vaginal bleeding, although there might not be any..
Abdominal pain..
Back pain..
Uterine tenderness or rigidity..
Uterine contractions, often coming one right after another..

What is it called when the placenta separates from the uterus?

Placental abruption means the placenta has detached from the wall of the uterus, either partly or totally. This can cause bleeding in the mother and may interfere with the baby's supply of oxygen and nutrients.

Which observation would indicate that the placenta has separated from the uterine wall and is ready for delivery?

Signs of placental separation The most reliable sign is the lengthening of the umbilical cord as the placenta separates and is pushed into the lower uterine segment by progressive uterine retraction.

What are the signs that the placenta has released from the uterine wall after birth?

Signs that the placenta is beginning to separate include: A sudden gush of blood. Lengthening of the visible portion of the umbilical cord. The uterus, which is usually soft and flat immediately after delivery, becomes round and firm.