Abruptio Placentae

Abruptio Placentae

Basics

Description

• Premature separation of an otherwise normally implanted placenta
• Grades:
  • Grade 1: Minimal or no bleeding; detected as retroplacental clot after delivery of viable fetus. Mild uterine irritability (40% of cases).
  • Grade 2: Viable fetus with bleeding and tender, irritable uterus. Mild-to-moderate bleeding; fibrinogen level decreased (45% of cases).
  • Grade 3: Type A with dead fetus and no coagulopathy; type B with dead fetus and coagulopathy (Types A and B = 15% of all cases)

Epidemiology

Incidence

• 0.5–1.2% of all deliveries:
  • Placental abruption is the most common cause of serious vaginal bleeding in late pregnancy (1).
• 15% if 1 prior abruption
• 25% if 2 or more prior abruptions
• 80% of cases occur prior to onset of delivery.
• Peaks at 24–26 weeks, then decreases with increasing gestation
• Rising in the US from 0.8% 1979–1981 to 1.2% 1999–2001

Risk Factors

• Prior abruption: Increases 15–20-fold (2)
• Increasing maternal age and parity
• Advanced maternal age
• Maternal smoking: dose–response relationship (2)
• Cocaine use and abuse
• Factor V Leiden and other thrombophilic disorders
• Hypertensive disorders
• Uterine anomalies
• Multiple-gestation pregnancies (3)[B]
• 1st- or 2nd-trimester bleeding
• Preeclampsia: Mild and severe
• Increased risk if hypertension and parity >3
• Preterm rupture of membranes (4)[B]
• Hydramnios
• Severe small-for-gestational-age birth
• Blunt trauma/motor vehicle accident

Genetics

• Genetic predisposition may be the cause of abruption in women with no other inciting factor discovered.
• Placental growth is primarily under control of paternally inherited fetal genes.

General Prevention

Eliminate risk factors when possible: Quit smoking and cocaine use, control hypertension, use seat belts, etc.

Pathophysiology

Exact cause is unknown: Appears to be the final common clinical event secondary to a variety of causes

Etiology

• Acute:
  • Trauma of variable amounts, especially blunt abdominal trauma in which external signs of trauma may be incongruent with fetal injury
  • Sudden decompression of overdistended uterus, as in hydramnios or twin gestation
  • Vasospasm secondary to cocaine use
• Chronic (majority of cases):
  • Hypertensive disorders and growth restriction associated with chronic process
  • Early bleeding in pregnancy releases thrombin, which is a potent uterotonic agent

Commonly Associated Conditions

• Preeclampsia and other forms of hypertension in pregnancy
• Uteroplacental insufficiency
• Postpartum hemorrhage
• Disseminated intravascular coagulation (DIC)
• Rupture of membranes

Diagnosis

History

• Classic triad of vaginal bleeding, abdominal pain, and contractions
• Abruption in prior pregnancy
• Early trimester bleeding
• Recent trauma
• Cocaine or tobacco use
• Back pain
• Frequent or tetanic contractions
• May present in active labor

Physical Exam

• Vital signs: Tachycardia, hypotension:
  • Because blood volumes increase in pregnancy, volume lost may exceed 30% before signs of shock or hypovolemia occur.
• Uterine tenderness, hypertonia, or high-frequency contractions
• Vaginal bleeding (not always present):
  • Clinical signs of shock may occur with little vaginal bleeding.
• Fetal distress or demise
• Idiopathic preterm labor with or without fetal distress

Diagnostic Tests & Interpretation

Lab

Initial lab tests

• Blood type, Rh, cross-match for possible transfusion:
  • RHoD immune globulin administered <12 weeks prior may affect antibody test.
• Complete blood count with platelet count
• Prothrombin time (PT)/partial thromboplastin time (PTT)
• Kleihauer-Betke test checks for evidence of fetal blood in maternal circulation; >30 mL fetal blood indicative of large fetal blood loss:
  • 300 µg dose of RhoGAM will cover up to 30 mL whole fetal blood in maternal circulation
• Bedside clot test: Red-top tube of maternal blood with poor or nonclotting blood after 7–10 minutes indicates coagulopathy.

Follow-Up & Special Considerations

• DIC can result from a large abruption. Best to stabilize patient without waiting for DIC labs. This is typically a clinical diagnosis.
• Can send PT/PTT, fibrinogen levels at clinician discretion when stable or following resolution of DIC:
  • Fibrinogen levels climb to 350–550 mg/dL in 3rd trimester and must fall to 100–150 mg/dL before PTT will rise.
  • Fibrin split or degradation products are elevated in pregnancy and are not specific in assessing DIC.

Imaging

Initial approach

• Placental abruption is a clinical diagnosis.
• Ultrasound can help to make the diagnosis, but has low sensitivity and is only helpful in cases of a large abruption.

Follow-Up & Special Considerations

Ultrasound: Appearance depends on size and location of the bleed:

• With acute bleed, nothing may be seen.
• Will fail to detect at least 50% of abruptions
• Retroplacental clot is diagnostic of abruption (2):
  • If incidental abruption is found in a patient at term, delivery is reasonable.
  • A preterm patient with an incidental abruption may be managed conservatively if stable.

Diagnostic Procedures/Surgery

• Tocometer often shows elevated baseline pressure and frequent low-amplitude contractions.
• External fetal monitoring may show recurrent late decelerations, variable decelerations, sinusoidal fetal heart tracing, bradycardia, or decreased variability—all indicative of fetal stress.

Pathological Findings

• Placental examination after delivery may show a retroplacental clot, pathologic signs of early separation/inflammation
• Normocytic normochromic anemia with acute bleeding
• Elevated PT/PTT, fibrinogen levels <100–150 mg/dL (1.0–1.5 g/L), platelets 20,000–50,000/µL if DIC is active
• Positive Kleihauer-Betke reaction if fetal–maternal transfusion has occurred
• Positive antibody if RhoD isosensitization has occurred

Differential Diagnosis

• Placenta previa or vasa previa (1)
• Uterine rupture
• Bloody show associated with labor
• Cervical and vaginal infections (e.g., chlamydia or gonorrhea with bloody, friable cervix)
• Other painful abdominal conditions (e.g., appendicitis, pyelonephritis)
• Fibroid degeneration
• Ovarian pathology: Torsed ovary, ruptured cyst

Treatment

Medication

First Line

• Tocolytics are generally contraindicated in presence of abruption:
  • Tocolytics, such as nifedipine or terbutaline, may be used in mild noncompromising preterm abruption (specific cases only, such as for fetal lung maturity)
• RhoD immune globulin for RhoD-negative mother if undelivered or indicated after delivery if Kleihauer-Betke is positive
• Fluid resuscitation as required for signs of shock

Second Line

• Transfuse packed red blood cells (PRBC) or other factors to stabilize patient as needed.
• Steroids for fetal lung maturation, if fetus is viable

Additional Treatment

Issues for Referral

• If preterm and hemodynamically stable, refer to tertiary care center.
• Alert anesthesia if delivery via cesarean section is likely.

Surgery/Other Procedures

• May need cesarean delivery after maternal stabilization if fetus is viable, remote from delivery, and nonreassuring fetal heart tracing is present.
• Postpartum hemorrhage/DIC may be treated medically or with uterine packing, embolization, or hysterectomy.

In-Patient Considerations

Initial Stabilization

• History and physical exam with medical history, allergies, prior ultrasounds (present gestation), and time of last meal
• Management depends on presentation, gestational age, and degree of maternal and fetal compromise:
  • In general, severe abruption is best managed by delivery of fetus.
  • Grade 1: Usual labor protocol
  • Grade 2: Rapid delivery, most often by cesarean delivery (if mother stable)
  • Grade 3: Vaginal delivery preferable if mother stable
• In trauma (2)[B], monitor in the inpatient setting for at least 4 hours for evidence of fetal insult, abruption, fetal–maternal transfusion. If contractions or preterm labor occur, patient should be monitored for at least 24 hours. Risk factors for contractions with trauma include:
  • Gestational age >35 weeks
  • Assaults and pedestrian/vehicular collisions, even without direct abdominal trauma
  • Ejections from vehicle or lack of restraints
• Early aggressive restoration of maternal physiology to protect fetus and maternal organs from hypoperfusion/DIC
• Stabilize vitals
• Bedrest with external fetal and labor monitoring, if fetus is viable
• Large-bore, 16- to 18-gauge IV crystalloid infusion to maintain volume
• Transfusions of whole blood and PRBCs as necessary
• Fresh frozen plasma and platelet transfusions for coagulopathy, with cryoprecipitate and fibrinogen given if indicated
• Follow hemoglobin/hematocrit and coagulation status.
• Consider internal monitoring of fetus if patient is in active labor.
• Role of amniotomy to prevent amniotic fluid embolism is debatable, but may speed delivery
• Positioning on left side may enhance venous return and cardiac output
• Oxygen as needed

Admission Criteria

Patients with suspected placental abruption should be admitted for workup until deemed clinically stable and ready for discharge/outpatient follow-up or delivered for medical indication.

IV Fluids

Saline or Ringer's lactate to restore maternal vascular volume

Nursing

• Bed rest until status defined
• Frequent vital sign monitoring
• Record fluid ins and outs

Discharge Criteria

• 2nd trimester suspected abruption may be managed on outpatient basis if hemodynamically stable
• Viable patients may be discharged if maternal/fetal status is stable.

Ongoing Care

Follow-Up Recommendations

• Monthly growth ultrasonograms for those patients where conservative management is possible.
• Serial ultrasounds may also be used to follow regression or progression of abruption (2).

Patient Monitoring

Severe cases or unstable patients may require critical care unit admission.

Diet

n.p.o. until status is defined and possibility of immediate cesarean delivery ruled out

Patient Education

• Call physician or proceed to hospital whenever patient experiences vaginal bleeding or if severe uterine or back pain or decreased fetal movement occurs.
• Wear seat belts while in automobile.
• Discontinue use of cocaine, tobacco
• Visit Mayo Health: http://mayohealth.org

Prognosis

• 0.5–1% fetal mortality and 30–50% perinatal mortality:
  • 1/2 of perinatal deaths due to preterm delivery
• With trauma and abruption, 1% maternal and 30–70% fetal mortality

Complications

• Maternal complications include anemia, stroke, myocardial infarction, DIC, and Sheehan's syndrome, and may include maternal death with severe hemorrhage.
• Surgical interventions and transfusion carry their own morbidity/mortality.
• Amniotic fluid embolism is rare, but may present with severe respiratory distress.