Abruptio Placentae (Placenta Abruptio)

Blausen 0737 PlacentalAbruption[1]

Abruptio placentae refers to placental separation from the uterus before delivery. Depending on the severity of separation, the condition may affect both mother and the fetus. The effect on the condition may also depend on the gestational age at the time of onset. 

This disorder is the result of the following process: anatomic/foreign.

Presentation

Vaginal bleeding is the most common symptom of abruptio placentae and is seen in 80% of the cases. The severity of bleeding varies from patient to patient and may not correspond to the extent of placental abruption. Abdominal/back pain, and tenderness in the uterus are also very common, and are seen in 70% of the patients presenting with placental abruption. About 60% of the cases present with fetal distress. Frequency of uterine contractions increases in some patients. Some patients may have to go for premature labor to alleviate fetal or maternal distress. Pain, both abdominal and back, often have a sudden onset. In some cases, bleeding may be limited to the uterine cavity without any external signs. This is more serious as the amount of bleeding is often underestimated.

Workup

Clinical diagnosis is the most common diagnostic feature for abruptio placentae. Sensitive and reliable confirmatory diagnostic tests are very rare for this condition. Class 0 abruptio placentae is usually diagnosed retrospectively based on the presence of blood clot or a depression in placenta. Physical examination is very important in identifying the origin of hemorrhage in patients who present with bleeding. Prompt stabilization of the patient is also equally important. Severe abruption can be identified by the presence of tense and tender uterus. Imaging techniques like ultrasound may not be effective in diagnosis as it is difficult to distinguish the blood clot from placenta. But his method is often used to rule out other causes of bleeding in the third trimester. Retroplacental clot, concealed hemorrhage, and expanding hemorrhage are all indicators of abruption. Clots may be hyperechoic to isoechoic initially, but this may change to hypoechoic within a week. Cardiotocograph is used to check for abnormalities in the fetal heart rate due to hypoxia.

Platelet count is often reduced in abruption and is often used to confirm the same. Coagulopathy is also common and is indicative of abruption. Coagulopathy is indicated by moderately reduced levels of fibrinogen. Sever abruption often result in fibrinogen level lesser than 200 mg/dL. Coagulation status of the patient is checked before cesarean section. Even with heavy bleeding, blood pressure of the patient may remain normal. This is because a healthy individual is able to tolerate significant loss of blood before presenting signs of decompensation. Other procedures may be recommended on the basis of gestational age, and fetal status. This includes fetal heart monitoring and type of delivery.

Treatment

Reattachment of the placenta to the uterine wall is not possible, and hence, treatment modality depends on the circumstance. Mother has to be resuscitated and stabilized before deciding on delivery, and is independent of gestation period. The criteria include – 1. Assess airway and breathing, 2. Evaluate circulation, and 3. Assess fetal status.

Treatment also depends on the quantity of blood lost and fetal distress. If the gestation period is less than 36 weeks, and there is no indication of maternal or fetal distress, only monitoring may be required. This is continued till the condition changes or until the maturity of the fetus, whichever comes first. Blood transfusion may be required based on blood loss.

Immediate delivery is indicated if there are signs of maternal or fetal distress, or if fetal maturity is attained. Blood transfusion is needed to maintain blood volume,  while platelet transfusion may be needed to maintain fibrinogen levels . Vaginal delivery is preferred if there are no indications of fetal distress, particularly if the mother is hemodynamically stable. Uterine tone and contractions increase, and this makes delivery rapid.

In the presence of disseminated intravascular coagulations, Cesarean section is preferred. For mothers with premature fetus and small placental separation, close observation is the method suggested. In case of excessive bleeding hysterectomy is recommended. Prior to hysterectomy, other procedures like correction of coagulopathy, ligation of uterine artery, administration of uterotonics, packing of uterus and control of hemorrhage are important.
If the fetus is premature, tocolytics are used for glucocorticoids administration. This will help to enhance maturation of fetal lungs. In case of chronic abruption this will help to delay delivery until complications are less. Tocolysis is induced by magnesium sulfate or nifedipine.

Prognosis

Prognosis depends on the extent of abruption, and also on promptness and quality of the treatment given. In more than half of the cases, fetal distress can be noted early in the condition. Infants have 40-50% chances of complications. Most of the complications are related to premature delivery which is done to alleviate fetal or maternal distress. Maternal morbidity may be caused by transfusion-related issues, cesarean delivery, and hysterectomy. Placental abruption may lead to shock, disseminated intravascular coagulation, acute blood loss, and failure of organs like kidney, in mother. In babies, placental abruption may lead to hypoxia and lack of nutrients, premature birth, or still birth.

Etiology

The actual cause of separation is unclear. Multiple factors are known to enhance the risk of abruptio placentae [1] [2]. Trauma or injury to abdomen due to fall or an accident is one of the direct causes of abruption. Sudden reduction in uterine volume due to an amniotic fluid loss or multiple pregnancy, is also implicated in the separation of placenta from uterine wall. Factors that increase the risk of the condition include

  • History of placental abruption
  • Hypertension – whether primary or secondary, this is one of the most common risk factor for placental separation.
  • Substance abuse – smoking and cocaine use during pregnancy increase the risk of abruption. One of the studies report that risk of abruption increase by 40% for an year indulged in smoking prior to pregnancy. Risk of abruption in cocaine users depends on the dose and is reported to range from 13% to 35% [3].
  • Premature rupture of membranes – break or leak of amniotic sac before labor results in reduced amniotic fluid, increasing the risk of placental separation.
  • Blood-clotting disorders 
  • Multiple pregnancy – Changes in the uterus after the first delivery in a twin gestation may cause placental separation before the delivery of other babies. 
  • Maternal age – risk of placental abruption is more in women above the age of 40 years. 

Epidemiology

Incidence of abruption placentae is about 1 in 150 deliveries. This abruption is severe in approximately one in 800 to 1,600 deliveries. Separation of placentae usually occurs during the third trimester, but may also happen after 20 weeks of gestation. Placental abruption is one of the most common causes of antepartum hemorrhage accounting to 30% of all cases [4]. Risk of placental abruption is more in young women below 20 years of age, and those above 40 years.

Sex distribution
Age distribution

Pathophysiology

Avulsion of placental villi from the lower uterine segment results bleeding into the decidua basalis. This abruption may be caused by any of the etiological factors. Hemorrhage into dedicua basalis pushes the placenta further away from the uterine wall and this in turn increases bleeding, resulting in a vicious cycle. Abruption of placentae may be classified into

  • Class 0 – this is the asymptomatic form of placental abruption.
  • Class 1 – this is characterized by vaginal bleeding with uterine tenderness . It is less serious as fetal or maternal distress is not present. This type accounts for 48% of all cases. 
  • Class 2 – this is a moderate form of abruption characterized by bleeding with some amount of fetal distress. This form is seen in 27% of all cases of placental abruption.
  • Class 3 – this is the most severe form of abruption placentae and is characterized by severe maternal bleeding, shock, and death of fetus. Maternal disseminated intravascular coagulation might also be noted. With forced entry of blood into the serosa, it may result in couvelaire uterus. 

Prevention

Eliminating risk factors is the best way to prevent abruptions in subsequent pregnancies. Smoking and cocaine use are two most important risk factors which can be completely avoided. Rehabilitation programs and education about the risk associated with its use will help in spreading awareness.

Summary

Abruptio placentae, commonly known as placental abruption, is an uncommon complication during pregnancy, characterized by premature separation of placenta from the uterine wall. This is a serious condition as placenta is a structure developed during gestation for nourishment of developing fetus. Abruptio placentae result in heavy bleeding and also deprives the fetus of oxygen and nourishment. The two main forms of abruption placentae are
Concealed abruption – refers to a condition in which bleeding is limited to uterine cavity and hence blood loss is underrated in most of the cases. It is seen in 20% of the cases and is more serious than revealed form of abruption
Revealed abruption – this form is characterized by bleeding and incomplete separation of placenta from the uterus. It is more common than concealed form and is less serious.
This condition may be categorized on the basis of extent of separation as partial or complete abruption. On the basis of location of separation, placental abruption is grouped into marginal and central abruption. Patients with placental abruption present with heavy bleeding, contractions and fetal distress. It has a sudden onset and is a serious condition that requires medical attention.

Patient Information

Abruptio placentae is commonly known as placental abruption, and is characterized by the separation of placenta from the uterine lining. This is an uncommon complication in pregnancy, and reduce oxygen and nutrition for fetus. It may cause heavy bleeding and fetal distress. The actual cause of the condition is not yet known. Risk of abruption is increased by factors  like smoking, cocaine or substance abuse, age above 40 years, high blood pressure, uterine infection, water breakage before 37 weeks of pregnancy, history of abruption in earlier pregnancy, uterus or umbilical cord problems, multiple pregnancies like twins or triplets, or injury or trauma to abdomen.

Patients with placental abruption often present with heavy bleeding, abdominal pain, back pain, uterine contractions, and fetal distress. Many complain of sudden belly and back pain. They may also have discomfort or tenderness in the belly. If the blood is limited in the uterine cavity, bleeding may be absent. Physical examination is the most common diagnostic procedure to identify uterine tenderness or rigidity. The actual cause of vaginal bleeding may be checked using ultrasound. This imaging technique is useful in the diagnosis of most form of abruptions.

Abruptio placentae is  serious and requires immediate medical attention. In some cases, the doctor may be able to indicate chances of abruption even before the separation happens. Treatment is based on the gestational age and also the severity of separation. If the fetus is premature and abruption is mild, close monitoring is the only recommendation. Medications may be given for maturation of fetal lungs, of delivery is necessary. If the fetus is full-term or near full-term with minimal placental abruption, vaginal delivery is suggested. If abruption may interrupt normal delivery, C-section may be needed. Prevention of abruption is not possible. The risk of placental separation can be reduced by quitting smoking or abuse of cocaine. Controlling blood pressure and avoiding accidents also help to reduce the risk of abruption placentae.

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References

  1. Abu-Heija A, al-Chalabi H, el-Iloubani N. Abruptio placentae: risk factors and perinatal outcome. J Obstet Gynaecol Res. 1998 Apr. 24(2):141-4.
  2. Oyelese Y, Ananth CV. Placental abruption. Obstet Gynecol. 2006 Oct. 108(4):1005-16.
  3. Hoskins IA, Friedman DM, Frieden FJ. Relationship between antepartum cocaine abuse, abnormal umbilical artery Doppler velocimetry, and placental abruption. Obstet Gynecol. 1991 Aug. 78(2):279-82.
  4. Neilson JP. Interventions for treating placental abruption. Cochrane Database Syst Rev. 2003;(1):CD003247.

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Media References

  1. Blausen 0737 PlacentalAbruption, CC BY 3.0
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