Placental abruption

Placental abruption
Classification and external resources
Ultrasound showing placental abruption.
ICD-10	O45
ICD-9	641.2
DiseasesDB	40
MedlinePlus	000901
eMedicine	med/6 emerg/12
MeSH	D000037

Illustration depicting internal and external bleeding from placental abruption

Placental abruption (also known as abruptio placentae) is a complication of pregnancy, wherein the placental lining has separated from the uterus of the mother. It is the most common pathological cause of late pregnancy bleeding. In humans, it refers to the abnormal separation after 20 weeks of gestation and prior to birth. It occurs in 1% of pregnancies worldwide. Placental abruption is a significant contributor to maternal mortality worldwide; early and skilled medical intervention is needed to ensure a good outcome, and this is not available in many parts of the world. Treatment depends on how serious the abruption is and how far along the woman is in her pregnancy.^[1]

Placental abruption has effects on both mother and fetus. The effects on the mother depend primarily on the severity of the abruption, while the effects on the fetus depend on both its severity and the gestational age at which it occurs.^[2] The heart rate of the fetus can be associated with the severity.^[3]

Lasting effects

On the mother:

• A large loss of blood or hemorrhage may require blood transfusions and intensive care after delivery. 'APH weakens for PPH to kill'.
• The uterus may not contract properly after delivery so the mother may need medication to help her uterus contract.
• The mother may have problems with blood clotting for a few days.
• If the mother's blood does not clot (particularly during a caesarean section) and too many transfusions could put the mother into disseminated intravascular coagulation (DIC) due to increased thromboplastin, the doctor may consider a hysterectomy.
• A severe case of shock may affect other organs, such as the liver, kidney, and pituitary gland. Diffuse cortical necrosis in the kidney is a serious and often fatal complication.
• In some cases where the abruption is high up in the uterus, or is slight, there is no bleeding, though extreme pain is felt and reported.

On the baby:

• If a large amount of the placenta separates from the uterus, the baby will probably be in distress until delivery and may die in utero, thus resulting in a stillbirth.
• The baby may be premature and need to be placed in the newborn intensive care unit. He or she might have problems with breathing and feeding.
• If the baby is in distress in the uterus, he or she may have a low level of oxygen in the blood after birth.
• The newborn may have low blood pressure or a low blood count.
• If the separation is severe enough, the baby could suffer brain damage or die before or shortly after birth.
• The newborn may have learning issues at later development stages, often requiring professional pedagogical aid.

Symptoms

• contractions that don't stop (and may follow one another so rapidly as to seem continuous)
• pain in the uterus
• tenderness in the abdomen
• vaginal bleeding (sometimes)
• uterus may be disproportionately enlarged
• pallor

Clinical Manifestation

• Class 0: asymptomatic. Diagnosis is made retrospectively by finding an organized blood clot or a depressed area on a delivered placenta.
• Class 1: mild and represents approximately 48% of all cases. Characteristics include the following:
  • No vaginal bleeding to mild vaginal bleeding
  • Slightly tender uterus
  • Normal maternal BP and heart rate
  • No coagulopathy
  • No fetal distress
• Class 2: moderate and represents approximately 27% of all cases. Characteristics include the following:
  • No vaginal bleeding to moderate vaginal bleeding
  • Moderate-to-severe uterine tenderness with possible tetanic contractions
  • Maternal tachycardia with orthostatic changes in BP and heart rate
  • Fetal distress
  • Hypofibrinogenemia (i.e., 50–250 mg/dL)
• Class 3: severe and represents approximately 24% of all cases. Characteristics include the following:
  • No vaginal bleeding to heavy vaginal bleeding
  • Very painful tetanic uterus
  • Maternal shock
  • Hypofibrinogenemia (i.e., <150 mg/dL)
  • Coagulopathy
  • Fetal death

Pathophysiology

Trauma, hypertension, or coagulopathy contributes to the avulsion of the anchoring placental villi from the expanding lower uterine segment, which in turn, leads to bleeding into the decidua basalis. This can push the placenta away from the uterus and cause further bleeding. Bleeding through the vagina, called overt or external bleeding, occurs 80% of the time, though sometimes the blood will pool behind the placenta, known as concealed or internal placental abruption.

Women may present with vaginal bleeding, abdominal or back pain, abnormal or premature contractions, fetal distress or death.

Abruptions are classified according to severity in the following manner:

• Grade 0: Asymptomatic and only diagnosed through post partum examination of the placenta.
• Grade 1: The mother may have vaginal bleeding with mild uterine tenderness or tetany, but there is no distress of mother or fetus.
• Grade 2: The mother is symptomatic but not in shock. There is some evidence of fetal distress can be found with fetal heart rate monitoring.
• Grade 3: Severe bleeding (which may be occult) leads to maternal shock and fetal death. There may be maternal disseminated intravascular coagulation. Blood may force its way through the uterine wall into the serosa, a condition known as Couvelaire uterus.

Risk factors

• Pre-eclampsia ^[2]
• Maternal smoking is associated with up to 90% increased risk.^[4]
  • See also: Smoking and pregnancy
• Maternal trauma, such as motor vehicle accidents, assaults, falls or nosocomial infection.
• Short umbilical cord
• Prolonged rupture of membranes (>24 hours)
• Thrombophilia ^[2]
• Retroplacental fibromyoma
• Multiparity ^[2]
• Multiple pregnancy^[2]
• Maternal age: pregnant women who are younger than 20 or older than 35 are at greater risk.
• Previous abruption: Women who have had an abruption in previous pregnancies are at greater risk.
• Previous Caesarean section^[2]
• some infections are also diagnosed as a cause
• cocaine intoxication^[5]

Prevention

Although the risk of placental abruption cannot be eliminated, it can be reduced. Avoiding tobacco, alcohol and cocaine during pregnancy decreases the risk. Staying away from activities which have a high risk of physical trauma is also important. Women who have high blood pressure or who have had a previous placental abruption and want to conceive must be closely supervised by a doctor.^[6]

The risk of placental abruption can be reduced by maintaining a good diet including taking folic acid, regular sleep patterns and correction of pregnancy-induced hypertension.

It is crucial for women to be made aware of the signs of placental abruption, such as vaginal bleeding, and that if they experience such symptoms they must get into contact with their health care provider/the hospital without any delay.

Intervention

Placental abruption is suspected when a pregnant mother has sudden localized abdominal pain with or without bleeding. The fundus may be monitored because a rising fundus can indicate bleeding. An ultrasound may be used to rule out placenta praevia but is not diagnostic for abruption. The mother may be given Rhogam if she is Rh negative.

Treatment depends on the amount of blood loss and the status of the fetus. If the fetus is less than 36 weeks and neither mother or fetus is in any distress, then they may simply be monitored in hospital until a change in condition or fetal maturity whichever comes first.

Immediate delivery of the fetus may be indicated if the fetus is mature or if the fetus or mother is in distress. Blood volume replacement to maintain blood pressure and blood plasma replacement to maintain fibrinogen levels may be needed. Vaginal birth is usually preferred over caesarean section unless there is fetal distress. Caesarean section is contraindicated in cases of disseminated intravascular coagulation. Patient should be monitored for 7 days for PPH. Excessive bleeding from uterus may necessitate hysterectomy.

Prognosis

The prognosis of this complication depends on whether treatment is received by the patient, on the quality of treatment, and on the severity of the abruption.

In the Western world, maternal deaths due to placental abruption are rare; for instance a study done in Finland found that, between 1972 and 2005 placental abruption had a maternal mortality rate of 0.4 per 1,000 cases (which means that 1 in 2,500 women who had placental abruption died); this was similar to other Western countries during that period.^[7] The prognosis on the fetus is worse, currently, in the UK, about 15% of fetuses die following this event.^[2]

Without any form of medical intervention, as often happens in many parts of the world, placental abruption has a high maternal mortality rate.

References

External links

• Emergency medicine: Abruptio Placentae, emedicine.com, April 5, 2005
• Obstetrics/Gynecology: Abruptio Placentae, emedicine.com, August 31, 2005
• Placental Abruption Awareness site: Click here for further information about Placental Abruption