Placental abruption
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Cafer Zorkun M.D., PhD.
Synonyms and keywords: Premature separation of placenta; ablatio placentae; abruptio placentae; placenta abruptio
Overview
Placental abruption is a complication of pregnancy, wherein the placental lining has separated from the uterus of the mother. It is the most common cause of late pregnancy bleeding. In humans, it refers to the abnormal separation after 20 weeks of gestation and prior to birth.
Classification
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.
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.
Lasting effects
On the mother:
- A large loss of blood or hemorrhage may require blood transfusions and intensive care after delivery.
- 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), the doctor may consider a hysterectomy.
- A severe case of shock may affect other organs, such as the liver, kidney, and pituitary gland.
- 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.
- 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.
Epidemiology and Demographics
It occurs in 1% of pregnancies world wide with a fetal mortality rate of 20-40% depending on the degree of separation. Placental abruption is also a significant contributor to maternal mortality. The heart rate of the fetus can be associated with the severity.[1]
Risk Factors
- Maternal hypertension is a factor in 44% of all abruptions.
- Maternal trauma, such as motor vehicle accidents, assaults, falls, or nosocomial
- Drug use is a factor, particularly tobacco, alcohol, and cocaine.
- Short umbilical cord
- Prolonged rupture of membranes (>24 hours)
- Retroplacental fibromyoma
- 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.
The risk of placental abruption can be reduced by maintaining a good diet including taking folic acid, regular sleep patterns and not smoking or drinking alcohol.
Diagnosis
Symptoms
- Contractions that don't stop
- Pain in the uterus
- Tenderness in the abdomen
- Vaginal bleeding (sometimes)
Treatment
Medical Therapy
Placental abruption is suspected when a pregnant woman has sudden localized uterine 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 previa but is not diagnostic for abruption. The mother may be given Rheogam 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 are 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 are in distress. Blood volume replacement and 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.
References
- ↑ Usui R, Matsubara S, Ohkuchi A; et al. (2007). "Fetal heart rate pattern reflecting the severity of placental abruption". doi:10.1007/s00404-007-0471-9. PMID 17896112.