Pre-eclampsia is a form of high blood pressure brought on by pregnancy. It is also known as pregnancy-induced hypertension (PIH) or toxemia. Eclampsia is seizures or convulsions caused by a severe form of pre-eclampsia.
Because it causes your blood vessels to constrict, pre-eclampsia reduces the amount of oxygen and nutrients delivered to your baby and can lead to low birth weight. Left untreated, it can also cause your liver, lungs, and kidneys to fail. Despite intensive research, no one knows exactly what causes the condition, and it continues to affect roughly 7 out of 100 pregnant women, humans are the only species that are known to get this disease, so animal research has not been helpful.
Pre-eclampsia appears during the second half of pregnancy, and is more likely to show up in first pregnancies, multiple births, teenagers, and women over 35. If you have chronic high blood pressure, a kidney disorder, or diabetes, you may be at higher risk for pre-eclampsia. If you've had the disorder before, the odds are 25% to 50% that you'll develop it in a future pregnancy as well. Additionally, if you have a new partner fathering this pregnancy your odds are increased that you will get pre-eclampsia in this pregnancy. And if your mother had the disorder you are also at increased risk. Those with the angotensinogen gene T235 have 20 times the average risk of developing this condition.
Eclampsia is much less common, afflicting only one in 1,500 pregnant women. It and the severe form of pre-eclampsia called the HELLP syndrome are thought to be caused by untreated pre-eclampsia, and results in convulsions that can put both you and your baby at risk. In very rare cases, eclampsia is fatal. If you get early, regular prenatal care, though, pre-eclampsia can be caught and treated, with little risk of progressing to eclampsia.
How Do I Know I Have It?
If you have mild pre-eclampsia, you may not notice any symptoms at all. But during each prenatal visit, your health-care provider will measure your blood pressure, test your urine, and be on the lookout for other early signs of the disease - a good reason not to miss any of your checkups.
Symptoms of mild pre-eclampsia include:
- Blood pressure of 140/90 or higher
- Swelling in your face and hands.
- Protein in your urine
The symptoms of severe pre-eclampsia are more obvious (fig. 1). They include:
- Constant, severe headaches
- Blurred vision or spots in front of your eyes (called scotomata)
- Sensitivity to light
- Nausea and vomiting
- Severe swelling
- Sudden weight gain of more than a pound a day
- Pain in the upper right side of your abdomen
- Shortness of breath
- Brisk reflexes (called hyperreflexia)
If pre-eclampsia isn't brought under control, the disease may progress to eclampsia. As pre-eclampsia worsens your urine protein may get progressively worse, you may have abnormal liver function tests, and your urine output may slow down (oliguria). The symptoms mirror those of severe pre-eclampsia, but also include:
- Unconsciousness or coma
How Is Pre-eclampsia Treated?
The treatment for pre-eclampsia is delivery. So if the disease is mild and you're within a few weeks of your due date, your doctor will induce labor. If you develop pre-eclampsia before your baby can be safely delivered, your doctor may recommend bed rest at home and consider antihypertensive medications to bring your blood pressure under control.
Your physician will also follow you closely by performing medical tests to see if your condition may be worsening, this may include a blood count to check for low platelets, a blood test of kidney function, or a 24-hour collection of urine to accurately determine how much protein you are putting out of your kidneys. Liver or kidney dysfunction is a sign of deterioration that would prompt your physician to deliver the baby early. If the baby is immature you may be a candidate for a steroid injection to mature the lungs. If your physician is uncertain if you need this treatment, an amniocentesis can be done to determine the maturity of your baby's lungs. If that doesn't work, you may have to check into the hospital for complete bed rest and observation, which allows the baby more time to mature. If your condition worsens or your baby shows signs of trouble, though, labor will be induced right away.
In severe cases, since the only known treatment is delivery, your doctor will induce labor regardless of your due date, since the risks of pre-eclampsia (kidney failure, severe bleeding, and eclampsia) outweigh the risks of premature delivery. She may also give you intravenous magnesium sulfate to prevent convulsions if eclampsia develops during labor.
If you have eclampsia, immediate delivery is required. Your doctor will give you intravenous magnesium sulfate to control the convulsions and may give you antihypertensive medication to lower your blood pressure.
After delivery, your doctor will monitor you closely and may keep you on anticonvulsant medication for a day or so. In almost all women, the symptoms of pre-eclampsia lessen a day or two after birth and vanish entirely within a week. If your blood pressure hasn't returned to normal by your six-week checkup, your doctor will look for other problems, such as a liver, blood, or kidney disorder.
How Can I Prevent It?
There is no known way to prevent pre-eclampsia, but with good prenatal care, you can catch the condition early and keep it under control. This involves seeing your caregiver often so she can keep tabs on your blood pressure and monitor the amount of protein in your urine.
Some studies show that taking low doses of aspirin every day may prevent pre-eclampsia from recurring. In countries where nutritional deficiencies are more common calcium supplementation has been proven to lower the risk of pre-eclampsia. If you had pre-eclampsia in a previous pregnancy, talk to your doctor about whether this makes sense for you.
Frequently Asked Questions (FAQ)
Q: If I develop pre-eclampsia during pregnancy, will I continue to have high blood pressure after giving birth?
A: Good news: There's no evidence that women who've had pre-eclampsia or eclampsia will develop high blood pressure later in life. To be on the safe side, though, make sure to have your blood pressure measured during your yearly medical checkup.
Q: I'm pregnant and my doctor says my blood pressure is high. Does this mean I have pre-eclampsia?
A: Not necessarily. Pre-eclampsia is almost always accompanied by other symptoms, such as protein in your urine and excessive swelling. Your doctor will continue to monitor your blood pressure and watch out for these symptoms. If they don't develop, then you probably won't get pre-eclampsia. Women who have chronic hypertension are more at risk to get superimposed pre-eclampsia than the general population.
Q: Will cutting out salt lower my chances of developing pre-eclampsia?
A: No. While too much sodium is never good, you need salt to help promote the flow of fluid in your body. Talk to your doctor about how much salt is safe to consume during pregnancy.
Review Date: July/16/2001
Reviewed By: A.D.A.M. Medical Illustration Team
Review Date: June 29, 2001
Reviewed By: Peter Chen, M.D., Obstetrics and Gynecology, University of
Pennsylvania School of Medicine. Review provided by VeriMed Healthcare
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