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Preeclampsia and Eclampsia

Pregnancy-Induced Hypertension (PIH), Toxemia of Pregnancy

What is Preeclampsia and Eclampsia?

Preeclampsia is a serious condition in which a pregnant woman develops high blood pressure (hypertension), fluid retention (edema), and protein or albumin in her urine (proteinuria) during the second half of pregnancy. Preeclampsia can be mild or severe, but if it is not controlled, it can lead to eclampsia. Eclampsia, which is characterized by seizures, can result in death of the mother and/or baby. Eclampsia occurs during late pregnancy, labor, or the period following delivery.

Affecting about six percent of pregnancies, preeclampsia is more common in first pregnancies and in mothers under 25 or over 35. Underlying conditions such as diabetes, hypertension, or kidney disease also increase the risk of preeclampsia. Eclampsia occurs more commonly in women who have had little or no prenatal care. The reason for this is that if preeclampsia does occur, it is not detected early enough, and so goes untreated. About half of all cases of eclampsia develop in late pregnancy, one third during labor, and the rest after delivery.

Although the exact cause is not known, both preeclampsia and eclampsia are thought to be caused by immunological dysfunction of the placenta (the organ in the womb that sustains the unborn child).

How is it diagnosed?

Preeclampsia is diagnosed largely from its symptoms. However, symptoms are not always apparent. The disorder is usually discovered during routine prenatal blood pressure checks and urine tests. As a result, regular prenatal care throughout a pregnancy is important for the diagnosis of preeclampsia.

Hypertension (high blood pressure) is one of the primary signs of preeclampsia. Typically, blood pressure is measured by wrapping an arm cuff (attached to a monitor) snugly around the patient's arm and then using a stethoscope to listen to the brachial artery located at the inside elbow on the same arm. The cuff is pumped full of air until circulation is briefly cut off. Then some air will be slowly let out of the device, loosening the cuff's grip on the arm and allowing the blood to flow freely again. As the air is let out, the examiner watches the numbers coming down on a simple monitor (sphygmomanometer) and waits until first hearing the heartbeat. The number at which that occurs is the systolic pressure. The examiner remembers this as the numbers continue to come down on the monitor and notes the number at which the heartbeat is last heard. The number at which that occurs is the diastolic pressure.

However, a high blood pressure measurement is not enough to diagnose preeclampsia. A reading above the normal range, or a reading that is significantly higher than a woman's normal blood pressure, will require close monitoring. The patient may be asked to visit the physician's office for additional blood pressure checks and urine tests at least once a week and possibly more often.

The urine tests will be used to detect protein in the urine, another major sign of preeclampsia. For this test, a sample of the patient's urine is collected. A chemically coated dipstick is then inserted into the urine to measure the amount of protein in the sample. Additionally, the patient may be asked to collect all of her urine over a 24 hour period of time to measure the total amount of protein in this specimen. When the patient has high blood pressure and proteinuria, blood tests may be ordered to verify the diagnosis.

The blood tests may focus on measuring the amount of platelets in the patient's blood. Thrombocytopenia (a platelet count less than 100,000) is a sign of preeclampsia.

The obstetrician-gynecologist (ObGyn) may also order blood tests to detect hemolysis (destruction of red blood cells), and to determine if the liver is functioning normally. Elevated liver function test results and hemolysis are signs of the condition.

In addition, the physician may recommend using ultrasound (a device that uses sound waves to produce an image of the uterus) to monitor the fetus' growth. The patient may also require a nonstress test (NST) or biophysical profile. These tests can be used to determine if the fetus is getting enough oxygen and nourishment. An NST is a non-invasive test that measures how often the fetus moves and how much its heart rate increases with each movement. A biophysical profile is a test that combines an ultrasound with an NST to reveal information about the fetus's breathing, movement and tone. It also provides information about the amount of amniotic fluid in the mother's uterus.

How is Preeclampsia and Eclampsia treated?

The treatment of mild preeclampsia is bedrest. The individual is usually hospitalized upon diagnosis to diminish the possibility of convulsions and to protect the fetus. Antihypertensive drugs or magnesium sulfate injections may be used to reduce blood pressure. In mild preeclampsia, individuals who can be relied on to follow physician instructions can be treated at home with bedrest, close monitoring of blood pressure, and daily urine tests (dipsticks) to monitor for protein.

The goal of treatment is to preserve the life and health of mother and infant. The only cure for preeclampsia and eclampsia is delivery. Therefore, the condition must be stabilized so that this may be accomplished. If the woman is close to term (at or beyond 36 weeks of pregnancy), or if eclampsia is imminent, labor may be induced (artificially started). The baby's condition is monitored by kick counts, non-stress tests, and ultrasound assessment of amniotic fluid volume.

Corticosteroids may be used to accelerate fetal lung development when it is thought that delivery may occur in two to seven days. In cases of eclampsia, the treatment is to control seizures and reduce high blood pressure. Anticonvulsants and antihypertensive drugs (used sparingly) are given by intravenous infusion. When the condition is stabilized, the baby is delivered (often by emergency cesarean section).

Once the baby is born, the mother's condition often resolves. However, because eclampsia may still occur in the two to four day period after delivery, continued observation (and prolonged hospitalization) may still be needed.


Valium (Diazepam), Normodyne (Labetalol)

What might complicate it?

Preeclampsia may require early delivery, which may create complications for the baby due to premature birth. One-third to one-half of babies fail to survive eclampsia. This is usually due to lack of oxygen in the uterus (uteroplacental insufficiency). Complications to the mother may include bleeding in the brain (cerebral hemorrhage), brain damage due to lack of oxygen (hypoxic encephalopathy), pneumonia caused by inhaling foreign matter into the lungs (aspiration pneumonia), generalized failure of blood clotting mechanism, rupture of the liver, or kidney (renal) failure.

Predicted outcome

After delivery, the mother's blood pressure usually returns to normal within a week, and the urine is cleared of protein within six weeks. Preeclampsia does not cause permanent damage or adversely affect the long-term health of the mother. Maternal deaths due to preeclampsia are rare. The prognosis is worse for the mother and fetus if the mother has a history of chronic high blood pressure.


Chronic hypertension can mimic preeclampsia.

Appropriate specialists

Obstetrician or gynecologist and perinatologist.

Notify your physician if

  • You or a family member has symptoms of preeclampsia at any stage of pregnancy.
  • The following occur during treatment:
    • Severe headache or vision disturbance.
    • Weight gain of 3 or more pounds in 24 hours.

Last updated 4 July 2015