Placental abruption and other obstetric abnormalities increase the risk of morbidity or mortality for the woman, fetus, or neonate.
Placental abruption occurs in 0.4 to 1.5% of all pregnancies; incidence peaks at 24 to 26 weeks gestation.
Placental abruption may involve any degree of placental separation, from a few millimeters to complete detachment. Separation can be acute or chronic. Separation results in bleeding into the decidua basalis behind the placenta (retroplacentally). Most often, etiology is unknown.
Risk factors for placental abruption include the following:
Older maternal age
Placental ischemia (ischemic placental disease) manifesting as intrauterine growth restriction Small-for-Gestational-Age (SGA) Infant Infants whose weight is < the 10th percentile for gestational age are classified as small for gestational age. Complications include perinatal asphyxia, meconium aspiration, polycythemia... read more
Other vascular disorders
Prior placental abruption
Premature rupture of membranes Prelabor Rupture of Membranes (PROM) Prelabor rupture of membranes is leakage of amniotic fluid before onset of labor. Diagnosis is clinical. Delivery is recommended when gestational age is ≥ 34 weeks and is generally indicated... read more , particularly in women who have polyhydramnios Polyhydramnios Polyhydramnios is excessive amniotic fluid; it is associated with maternal and fetal complications. Diagnosis is by ultrasonographic measurement of amniotic fluid volume. Management is by treating... read more
Complications of placental abruption include the following:
Maternal blood loss that may result in hemodynamic instability, with or without shock, and/or disseminated intravascular coagulation Disseminated Intravascular Coagulation (DIC) Disseminated intravascular coagulation (DIC) involves abnormal, excessive generation of thrombin and fibrin in the circulating blood. During the process, increased platelet aggregation and coagulation... read more (DIC)
Fetal compromise (eg, fetal distress, death) or, if placental abruption is chronic, growth restriction or oligohydramnios
Sometimes fetomaternal transfusion and alloimmunization (eg, due to Rh sensitization Hemolytic Disease of the Fetus and Neonate Hemolytic disease of the fetus and neonate is hemolytic anemia in the fetus (or neonate, as erythroblastosis neonatorum) caused by transplacental transmission of maternal antibodies to fetal... read more ).
Symptoms and Signs of Placental Abruption
Severity of symptoms and signs of placental abruption depends on the degree of separation and blood loss.
Acute placental abruption may result in uterine bleeding. Blood may also remain behind the placenta (concealed hemorrhage). As separation continues, the uterus may be painful, tender, and irritable to palpation. If placental abruption is completely or partially concealed, uterine pain and tenderness may appear out of proportion to the volume of bleeding.
Hemorrhagic shock may occur, as may signs of DIC.
Chronic placental abruption may cause continued or intermittent dark brown spotting.
In some cases, placental abruption causes no or minimal symptoms and signs.
Diagnosis of Placental Abruption
Fetal heart rate monitoring
Sometimes coagulation blood tests
Sometimes ultrasonographic findings
The diagnosis of placental abruption is suspected if any of the following occur after the 1st trimester:
Uterine pain and tenderness
Fetal distress or death
Placental abruption should also be considered in women who have had abdominal trauma. If bleeding occurs during middle or late pregnancy, placenta previa Placenta Previa Placenta previa is implantation of the placenta over or near the internal os of the cervix. It typically manifests as painless vaginal bleeding after 20 weeks gestation; the source of bleeding... read more , which has similar symptoms, must be ruled out before pelvic examination is done; if placenta previa is present, examination may increase bleeding.
Evaluation for placental abruption can include the following:
Fetal heart monitoring
CBC (complete blood count)
Blood and Rh typing
PT/PTT (prothrombin time/partial thromboplastin time)
Serum fibrinogen and fibrin-split products (the most sensitive indicator)
Kleihauer-Betke test if the patient has Rh-negative blood—to calculate the dose of Rho(D) immune globulin needed
The source of bleeding in placental abruption is maternal. However, the partial or complete separation of the placenta from the uterine wall compromises fetal oxygen exchange. Fetal heart rate monitoring may detect a nonreassuring pattern or fetal death.
Abnormal results of coagulation blood tests or fetal heart rate monitoring support the diagnosis.
Transvaginal ultrasonography is necessary if placenta previa is suspected based on transabdominal ultrasonography. Ultrasonography can show some cases of placental abruption. However, findings with either type of ultrasonography may be normal in placental abruption.
Pearls & Pitfalls
Treatment of Placental Abruption
Sometimes prompt delivery and aggressive hemodynamic supportive measures (eg, in a term pregnancy or for maternal or possible fetal instability)
Trial of hospitalization for observation if the pregnancy is not near term and if mother and fetus are stable
Prompt cesarean delivery is usually indicated if placental abruption plus any of the following is present:
Maternal hemodynamic instability
Nonreassuring fetal heart rate pattern
Term pregnancy (≥ 37 weeks); preterm delivery possibly necessary if the mother or fetus is at risk of severe morbidity or mortality
Once delivery is deemed necessary, vaginal delivery may be attempted if all of the following are present:
The mother is hemodynamically stable.
The fetal heart rate pattern is reassuring.
Vaginal delivery is not contraindicated (eg, by placenta previa or vasa previa).
Labor may be carefully induced or augmented (eg, using oxytocin and/or amniotomy). Preparations for postpartum hemorrhage Postpartum Hemorrhage Postpartum hemorrhage is blood loss of > 1000 mL or blood loss accompanied by symptoms or signs of hypovolemia within 24 hours of birth. Diagnosis is clinical. Treatment depends on etiology... read more should be made.
Hospitalization and observation are advised if all of the following are present:
Bleeding does not threaten the life of the mother or fetus.
The fetal heart rate pattern is reassuring.
The pregnancy is preterm (< 37 weeks).
This approach ensures that mother and fetus can be closely monitored and, if needed, rapidly treated. Women should be advised to refrain from sexual intercourse.
Corticosteroids should be considered (to accelerate fetal lung maturity) if gestational age is < 34 weeks. Corticosteroids may also be given if all of the following are present:
The pregnancy is late preterm (34 to 36 weeks).
The mother has not previously received corticosteroids during this pregnancy and has no contraindications.
Risk of delivery in the late preterm period is high (1 Treatment reference Placental abruption (abruptio placentae) is premature separation of the placenta from the uterus, usually after 20 weeks gestation. It can be an obstetric emergency. Manifestations may include... read more ).
If bleeding resolves and maternal and fetal status remains stable, ambulation and usually hospital discharge are allowed. If bleeding continues or if status deteriorates, prompt cesarean delivery may be indicated.
Complications of placental abruption (eg, shock, DIC) are managed with aggressive replacement of blood and blood products.
Placental abruption is premature separation of the placenta from the uterus and can be an obstetric emergency.
It typically manifests as uterine bleeding and uterine pain or tenderness; bleeding varies in volume and acuity and, if the abruption is concealed, may be absent.
Diagnose based on characteristic symptoms and signs.
Ultrasonography can show some cases of abruption; results of abnormal coagulation blood tests or fetal heart rate monitoring support the diagnosis.
Manage with prompt cesarean delivery if maternal or fetal stability is threatened or if pregnancy is at term.
Consider vaginal delivery if mother and fetus are stable and pregnancy is at term.