Although the causes of preeclampsia and eclampsia are unknown, researchers believe that damage to the lining of the blood vessels contributes to the rise in blood pressure and other abnormal functions and symptoms that develop in preeclampsia. As blood pressure rises, the brain's system for regulating vascular activity is altered, which causes spasms, seizures, increased blood pressure, and other complications.

Substances called prostaglandins constrict and dilate blood vessels. Early research showed that women with preeclampsia have altered prostaglandin ratios. This raised the question of whether substances that inhibit prostaglandin production-such as aspirin (for example, Bufferin or Ecotrin) and calcium (for example, oyster shell calcium or Os-Cal)-could prevent preeclampsia.

In the past, aspirin was used to treat high-risk patients. Currently, however, this treatment is generally contraindicated. In several small studies, low doses of aspirin reduced the incidence of preeclampsia in high-risk populations. However, in 1994, the Collaborative Low-Dose Aspirin Study in Pregnancy (CLASP) Collaborative Group reported a large, randomized trial comparing low-dose aspirin to placebo (sugar pills) in more than 9,300 high-risk patients. Low-dose aspirin did not reduce the incidence of preeclampsia in these patients. Overall, evidence does not confirm the benefit of low-dose aspirin as a preventive treatment for high- or low-risk women.

Currently, no medications or dietary supplements have been shown to be beneficial in the prevention of preeclampsia. Your doctor may recommend evaluation of your blood pressure, kidney function, and blood clotting as preventative treatments. Weight reduction and good blood sugar control (if you are diabetic) may also lower your risk for preeclampsia.

In general, the best way to avoid problems during pregnancy-or to manage them effectively if they do arise-is to see your doctor regularly. Begin prenatal care at the start of your pregnancy and keep all your scheduled prenatal visits.

If you do develop preeclampsia during pregnancy, you and your baby are monitored regularly. Your treatment may include self-measured blood pressure and restricted activity. The more severe your preeclampsia, the more likely your need for hospitalization, close monitoring, and early delivery of your baby.