Preeclampsia, previously known as toxemia, is the sudden increase in blood pressure of a pregnant woman. If this condition occurs it is usually by the 20th week of pregnancy, resulting in hypertension and, usually, elevated protein levels in the urine. Preeclampsia, if left untreated, can result in serious complications for both mother and fetus. Eclampsia is a more severe form of preeclampsia.
Causes of Preeclampsia
While the precise cause of preeclampsia is unknown, the condition is believed to originate in the placenta. In women who develop preeclampsia, the new blood vessels that develop early in pregnancy to send blood to the placenta do not develop normally. Some possible causes for this abnormal blood vessel development include:
- Insufficient blood flow to the uterus
- Damaged blood vessels
- Malfunction of the immune system
Certain gene mutations are associated with preeclampsia.
Risk Factors for Preeclampsia
There are several known risk factors for developing preeclampsia. Preeclampsia is more likely if the woman:
- Is pregnant for the first time
- Has had a previous multiple birth
- Is obese
- Has diabetes, lupus or kidney disease
- Is a teenager or is older than 40
- Has a personal or family history of preeclampsia
- Has a history of hypertension
For unknown reasons, each pregnancy with a new birth father also increases the risk of preeclampsia, as does being pregnant twice in less than 2 years or becoming pregnant after a 10-year interval.
Symptoms of Preeclampsia
Frequently, preeclampsia develops unnoticed by the patient and is detected during a routine urine or blood pressure test. Other symptoms of preeclampsia are:
- Edema of the face and hands
- Sudden weight gain
- Upper abdominal pain
- Severe headache
- Dizziness, confusion, or anxiety
- Shortness of breath due to fluid in the lungs
- Changes in vision
- Nausea or vomiting
- Decreased urine output
While any of these symptoms are cause for concern in a pregnant woman, they may not be serious or even abnormal. Nonetheless, each warrants medical consultation and accurate diagnosis.
Diagnosis of Preeclampsia
Because many of the signs of preeclampsia are measurable through testing, it is important that pregnant women be checked regularly, whether or not they are experiencing symptoms. If a blood pressure reading is abnormally high, the test has to be repeated at intervals of at least 4 hours; a single abnormal reading is not sufficient to lead to even a tentative diagnosis of preeclampsia.
Repeated tests showing hypertension and protein in the urine (proteinuria) were once considered the telltale signs of preeclampsia. It is now known, however, that not all patients with preeclampsia have protein in the urine. Other diagnostic tests for preeclampsia include:
- Blood tests for low platelet levels
- Blood tests for liver and kidney function
- Blood and other tests for pulmonary edema
- Fetal ultrasound
- Nonstress test or biophysical profile of fetus
Treatment of Preeclampsia
Women diagnosed with preeclampsia require careful monitoring throughout the remainder of their pregnancies, including frequent blood tests, ultrasounds and nonstress tests. Because the only completely effective treatment for preeclampsia is the delivery of the baby, labor is usually induced in patients who are nearing the end of their pregnancies. These women, however, will still need to be monitored after they give birth.
Depending on how severe the preeclampsia is, the following medications may be prescribed:
- Antihypertensives to lower blood pressure
- Corticosteroids to improve liver and platelet function
- Anticonvulsant medications to prevent seizures
Corticosteroids may also help to accelerate the development of the fetus's lungs which is essential if the baby has to be delivered prematurely.
Bed rest is often prescribed for women diagnosed with preeclampsia early in their pregnancies, with patients spending most of their time on their left sides. In severe cases of preeclampsia, patients may be hospitalized so that they and their babies can be more carefully monitored.
Complications of Preeclampsia
Though preeclampsia can present a danger to both the mother and the baby, with careful watching and necessary medical intervention, complications, are rare.
For the mother-to-be, preeclampsia increases the risk of seizures, heart failure, bleeding from the liver, temporary blindness and excessive bleeding after parturition.
For the baby, preeclampsia may be responsible for a premature birth or a low birth weight. Premature and low birth weight babies have increased risk of birth defects. Preeclampsia can also cause a sudden detachment of the placenta from the uterus which may result in a stillbirth.