Hypertension/High Blood Pressure Health Center

Understanding Preeclampsia and Eclampsia -- the Basics

What Are Preeclampsia and Eclampsia?

Preeclampsia and eclampsia are diseases of pregnancy that involve the development or worsening of high blood pressure during pregnancy. As the names suggest, these two disorders are related. Preeclampsia, also called "toxemia of pregnancy," may develop into the more severe condition called eclampsia. Eclampsia includes symptoms of preeclampsia together with seizures.

These conditions, when they develop, usually occur during the second half of pregnancy -- after 20 weeks -- although they may also develop shortly after delivery. In very rare situations, they occur before 20 weeks of pregnancy.

High blood pressure is dangerous during pregnancy, since it may interfere with the placenta's ability to deliver oxygen and nutrition to your fetus. Your baby may be born weighing less than normal, may have other health problems, and may need to be delivered early or by cesarean birth.

If your blood pressure continues to climb higher, your kidneys may have trouble functioning. You may have changes in the makeup of your blood, such as a destruction of red blood cells (causing anemia), as well as disturbed liver function and decreased platelets (the blood cells involved in clotting). Too few platelets can increase your risk of bleeding uncontrollably during delivery or even spontaneously.

If your blood pressure continues to climb, you may develop seizures. Once you begin to have seizures, you're considered to have eclampsia. This is a life-threatening situation for both you and your baby. During a seizure, you and your baby are at risk of being deprived of oxygen. In addition, the high blood pressure may cause the placenta to begin to separate from the wall of the uterus, called a placental abruption. This can cause severe bleeding and even death of the fetus and possibly the mother.

Who Gets Preeclampsia and Eclampsia?

Preeclampsia affects 5% to 8% of all pregnancies. Any pregnant woman can get preeclampsia, but you're at increased risk of developing preeclampsia if:

• This is your first pregnancy.
• Your mother or sister had preeclampsia or eclampsia during pregnancy.
• You're carrying twins.
• You're African-American.
• You're younger than 20 or older than 40 at the time of pregnancy.
• You already have high blood pressure, kidney disease, or diabetes.
• You have a pre-pregnancy body mass index (BMI) greater than 30.

What Causes Preeclampsia and Eclampsia?

The cause of preeclampsia is still unclear, although some studies have indicated that it is related to poor nutrition. Other possible causes include injury to your blood vessels, a disruption in the hormones that maintain your blood vessels, or lack of magnesium or calcium. Eclampsia usually develops when preeclampsia goes unnoticed and untreated.