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What causes placental abruption?

by Ann Marie Dwyer

No known causes of placental abruption exist. By collecting information from obstetricians with patients, like this writer, who have had placental abruptions, statistics are compiled to determine risk factors.

Abruptio placentae occurs in less than one per cent of all pregnancies. Abruptions are the premature separation of the placenta from the uterine wall. Based on the stage of pregnancy, some abruptions are never reported.

*Types of abruption*
1. Mild or partial placental abruption
The most common of placental abruptions are partial separations. These are reported most frequently in women who have had four or more pregnancies, have diabetes or high blood pressure.

Diagnosis of partial abruption is made by ultrasound, which will reveal a blot clot between the placenta and the uterine wall. Blood tests and fetal monitoring can determine if partial abruption is occurring.

If the fetus is not in distress and the mother's health is not at risk, physicians advise the patient to restrict activities, including sex, and frequent check ups until natural birth.

2. Moderate placental abruption
Once diagnosed, physicians admit the mother to the hospital for intravenous (IV) fluid, fetal monitoring and testing to determine if further measures are needed.

If the fetus has a stable heartbeat and is not in distress, the hospital tests for the mother's ability to clot, blood pressure, pulse and urinary output. Some cases require blood or platelet transfusion to increase clotting ability to heal the abruption.

Based on gestation stage (after week 34), the obstetrician may induce labor to reduce further risk to mother and child.

3. Severe placental abruption
When more than half of the placental connection to the uterine wall is lost, the risks to mother and child are great. The mother may hemorrhage and exsanguinate (bleed to death).

The baby may suffer brain damage that can be fatal just before or shortly after birth due to the lack of oxygen being transferred through the abrupted placenta. A decreased amount of nutrients leads to lower birth weight, prematurity and certain developmental delays.

If the fetus is in distress, abnormal or fluctuating heart rate, or the mother is in distress, high blood pressure or hemorrhaging, the obstetrician will deliver the baby by cesarean section regardless of gestation.

These premature deliveries result in babies that have problems breathing and feeding on their own because they are too immature.

*Risk factors for placental abruption*
The following conditions are noted in a predominant number of abruption cases. Most severe abruptions are associated with two or more risk factors.

1. Women pregnant over the age of 35
2. Women with four or more pregnancies
3. Cocaine users
4. Women pregnant with multiples
5. Hypertension (high blood pressure)
6. Diabetes
7. Prior placental abruption
8. Women requiring external cephalic version (moving the baby into the correct birthing position)
9. Women who suffer severe abdominal or vaginal trauma (rare)

*Symptoms of placental abruption*
Symptoms do not occur with all placental abruptions. Mild abruptions usually have no symptoms. If symptoms occur, seek the immediate advice of an obstetrician.

1. Vaginal bleeding (rare)
2. Abdominal pain over the uterus
3. Consistent contractions (do not stop during rest periods)
4. Uterine pain, including cervical pressure that triggers pushing reflex.
5. Premature dilation of the cervix

*Long term effects of placental abruption*
The mother should suffer no long term effects of mild abruption, which normally occurs and heals without incident.

Moderate to severe abruption can have the following effects on the mother after delivery:

1. Severe shock that affects the liver, pituitary gland or kidneys
2. Blood loss or continued hemorrhaging requiring transfusion and/or intensive post delivery care
3. Low platelet count that will inhibit clotting during the first days after delivery
4. Improper contraction of the uterus post delivery requiring medication to induce contractions
5. Increased risk of another placental abruption in subsequent pregnancies

The baby can suffer after moderate to severe abruption, to include the following:

1. Low levels of oxygen in the blood after delivery
2. Low blood pressure or low blood count
3. Brain damage stemming from lack of oxygen delivered through the abrupted placenta.
4. Death before or shortly after delivery

*Prevention*
Moderate to severe placental abruption is not reported in healthy pregnancies. Notify the obstetrician if pregnancy occurs after placental abruption.

Following the advice of an obstetrician about nutrients and vitamins, controlling diabetes and high blood pressure, cessation of illegal drugs and maintaining a regimen of good prenatal care including frequent doctor visits lower the chances of placental abruption.

Seek professional medical help from an obstetrician or hospital at the first sign of any symptoms.

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