Hypertension (high blood pressure) that develops after the twentieth week of pregnancy in a woman with no history of hypertension can either be gestational hypertension or preeclampsia. Distinguishing the two may be difficult.

Preeclampsia is characterized by protein in the urine (proteinuria) and swelling (edema). Gestational hypertension is high blood pressure without these additional symptoms. Either condition may be problematic, but preeclampsia generally poses more of a danger to both mother and baby.

Understanding Preeclampsia

Preeclampsia can lead to central nervous system problems (including blurred vision, headaches, and confusion), stroke, and kidney failure. Preeclampsia left untreated can lead to eclampsia, a serious life-threatening condition that can cause seizures. Preeclampsia usually ends at delivery.

Sometimes an especially serious variant of preeclampsia called HELLP syndrome can occur. It is characterized by involvement of the liver, red blood cells, and blood coagulation system. It can sometimes occur by itself, without preeclampsia.

Risks for Preeclampsia

Women over age 35 are twice as likely as younger women (whose risk is about 5 to 8 percent) to develop high blood pressure during pregnancy, one of the warning signs of preeclampsia. Women over 40 have a 60 percent chance of developing this. Risks are higher for women carrying multiples.

Having a mother or sister who had preeclampsia increases your risk. Risk is also elevated if your baby's father's mother had preeclampsia when pregnant with him. This may be a genetic form of preeclampsia, in which the unborn baby inherits the trait and actually causes the preeclampsia.

Preeclampsia is more common in a first pregnancy. If you develop preeclampsia in one pregnancy, you are more likely to develop it in subsequent pregnancies. Interestingly, smoking decreases the risk of preeclampsia (although it is not recommended as prevention) and the use of barrier contraception, such as condoms or the diaphragm, in the year prior to the pregnancy increases the risk.

Controlling Preeclampsia

In women at very high risk for preeclampsia (such as those with existing renal disease or hypertension), low-dose aspirin was effective in preventing preeclampsia. However, the study did not focus only on women over age 35. Bed rest or medications can be prescribed to control preeclampsia. Although reducing salt intake is recommended for other cases of hypertension, it is not a recommendation for high blood pressure during pregnancy, so don't try this as a solution.

If preeclampsia is becoming dangerous, induction of labor may be necessary, even if the baby is premature. Fortunately most preeclampsia occurs at the end of pregnancy, is mild, and can easily be managed by delivery.