Preeclampsia (which used to be called toxemia of pregnancy) is a pregnancy-related blood circulation problem that causes high blood pressure and affects the mother's kidneys, liver, brain, and placenta. Its cause is unknown.

Preeclampsia most commonly occurs during first pregnancies.

Signs of preeclampsia include:

• Elevated blood pressure (generally 140/90 millimeters of mercury [mm Hg] or higher). This could be higher systolic blood pressure (the first number), or higher diastolic blood pressure (the second number), or both. Any large increase in blood pressure should alert a woman and her doctor to possible risk.
• Persistent headache.
• Vision problems.
• Pain in the upper right abdomen.
• Lab results indicating elevated uric acid and/or protein in the urine (proteinuria).
• Swelling of the hands and face that does not go away during the day. This symptom of normal pregnancy may be a sign of preeclampsia if it is accompanied by other signs of preeclampsia.

Preeclampsia typically occurs after the 20th week of pregnancy. It can develop much earlier in a multiple or molar pregnancy than in a normal pregnancy. Preeclampsia can develop gradually or suddenly and may remain mild or become severe.

A woman with any signs of preeclampsia is closely monitored by her doctor or nurse-midwife. Preeclampsia can be treated in the hospital with bed rest, medicine, and close monitoring of the mother and fetus. If not treated, preeclampsia may damage the mother's liver or kidneys and can cause seizures (eclampsia). In rare cases, coma and death of the mother and fetus can follow.

Delivery is the only true "cure" for preeclampsia. This has to be balanced with how far along the pregnancy is and whether it is safe for the fetus to be delivered. Within the first few days following delivery, the mother's blood pressure usually returns to normal. With severe preeclampsia, it may take at least 6 weeks for blood pressure to return to normal.