hypertensive conditions that are induced by pregnancy. Preeclampsia, also called gestational edema-proteinuria-hypertension (GEPH), is an acute toxic condition arising during the second half of the gestation period or in the first week after delivery and generally occurs in young women during a first pregnancy. It is marked by elevated blood pressure ( hypertension), protein in the urine ( proteinuria), and swelling ( edema) that is strikingly noticeable in the hands and face. Eclampsia, a more severe condition with convulsions (convulsion), follows preeclampsia in about 5 percent of preeclamptic women and poses a serious threat to both mother and child.

The underlying causes of preeclampsia and eclampsia remain unclear. The primary clinical feature of elevated blood pressure may be attributed to malformed blood vessels (blood vessel) feeding into the placenta from the uterus. Abnormal or damaged vessels can trigger the release of inflammatory substances and other molecules (e.g., angiotensin) that cause vessel inflammation or constriction. Other possible causes of preeclampsia and eclampsia include genetic defects, autoimmune (autoimmunity) disorders, and diet. One gene believed to be susceptible to defects that predispose some women to preeclampsia is catechol-O-methyltransferase (COMT), which produces an enzyme. Scientists suspect that the enzyme and its major metabolite called 2-methoxyestradiol (2-ME) are required for normal formation and function of placental vasculature. Lack of the COMT enzyme and therefore 2-ME has been linked with persistent placental hypoxia—a decrease in oxygen in placental tissue that is considered a hallmark of preeclampsia. Hypoxia, which stimulates the formation of new blood vessels, is normal in the first trimester of pregnancy and ensures sufficient delivery of nutrients and oxygen to the rapidly growing fetus. By the third trimester, the demand for new vessels drops and new vessel formation is halted—a process controlled by 2-ME. Prolonged exposure to hypoxia endangers the health of the fetus and the mother and is the primary reason premature delivery may be necessary in preeclamptic pregnancies.

Common symptoms of preeclampsia include headaches (headache), visual disturbances, and stomach pain; however, it may be detected before the onset of symptoms by monitoring blood pressure and weight gain. Preeclampsia can often be controlled by special diets, medication, and limitation of activity. If it occurs late in pregnancy, there is the option of early delivery. Eclampsia can usually be avoided by these measures. If convulsions occur, they are treated with infusions of magnesium sulfate.