Abruptio placentae and other obstetric abnormalities increase the risk of morbidity or mortality for the woman, fetus, or neonate.
Abruptio placentae occurs in 0.4 to 1.5% of all pregnancies; incidence peaks at 24 to 26 weeks gestation.
Abruptio placentae 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 abruptio placentae 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, and... read more
Other vascular disorders
Prior abruptio placentae
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. Maternal disorders contributing... read more
Complications of abruptio placentae 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 abruptio placentae is chronic, growth restriction or oligohydramnios
Sometimes fetomaternal transfusion and alloimmunization (eg, due to Rh sensitization Erythroblastosis Fetalis Erythroblastosis fetalis is hemolytic anemia in the fetus (or neonate, as erythroblastosis neonatorum) caused by transplacental transmission of maternal antibodies to fetal red blood cells.... read more ).
Symptoms and Signs of Abruptio Placentae
Severity of symptoms and signs depends on the degree of separation and blood loss.
Acute abruptio placentae may result in bright or dark red blood exiting through the cervix (external hemorrhage). Blood may also remain behind the placenta (concealed hemorrhage). As separation continues, the uterus may be painful, tender, and irritable to palpation.
Hemorrhagic shock may occur, as may signs of DIC. Chronic abruptio placentae may cause continued or intermittent dark brown spotting.
Abruptio placentae may cause no or minimal symptoms and signs.
Diagnosis of Abruptio Placentae
Clinical evaluation, sometimes plus laboratory and ultrasonographic findings
The diagnosis of abruptio placentae is suspected if any of the following occur after the 1st trimester:
Vaginal bleeding (painful or painless)
Uterine pain and tenderness
Fetal distress or death
Tenderness or shock disproportionate to the degree of vaginal bleeding
Abruptio placentae 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. Typically, painless vaginal bleeding with bright red blood occurs after 20 weeks gestation. Diagnosis... 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 abruptio placentae includes 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)
Transabdominal or pelvic ultrasonography
Kleihauer-Betke test if the patient has Rh-negative blood—to calculate the dose of Rho(D) immune globulin needed
Fetal heart monitoring may detect a nonreassuring pattern or fetal death.
Transvaginal ultrasonography is necessary if placenta previa is suspected based on transabdominal ultrasonography. However, findings with either type of ultrasonography may be normal in abruptio placentae.
Pearls & Pitfalls
Treatment of Abruptio Placentae
Sometimes prompt delivery and aggressive supportive measures (eg, in a term pregnancy or for maternal or possible fetal instability)
Trial of hospitalization and modified activity if the pregnancy is not near term and if mother and fetus are stable
Prompt cesarean delivery is usually indicated if abruptio placentae plus any of the following is present, particularly if vaginal delivery is contraindicated:
Maternal hemodynamic instability
Nonreassuring fetal heart rate pattern
Term pregnancy (≥ 37 weeks)
Once delivery is deemed necessary, vaginal delivery can 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 can 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 modified activity (modified rest) 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. (Modified activity involves refraining from any activity that increases intra-abdominal pressure for a long period of time—eg, women should stay off their feet most of the day. 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 any corticosteroids.
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 abruptio placentae (eg, shock, DIC) are managed with aggressive replacement of blood and blood products.
Bleeding in abruptio placentae may be external or concealed.
Sometimes abruptio placenta causes only minimal symptoms and signs.
Do not exclude the diagnosis because a test result (including ultrasonographic) is normal.
Consider 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.