There was a time--just a few decades ago--when pregnancy was considered relatively dangerous.
Today, because of improved medical care, a woman's risk of serious complications or death during pregnancy and delivery is extremely low. Nevertheless, one serious problem continues to plague pregnant women and obstetricians: preeclampsia.
During the last decade, the rate of preeclampsia has increased by nearly one-third, and the condition currently affects about 8% of all pregnancies. In women with preeclampsia, arteries throughout the body constrict, narrowing the opening through which blood can flow and diminishing the blood supply to virtually all organs in the body, including the placenta and fetus. This narrowing of the vessels also causes blood pressure to rise, sometimes to dangerous levels.
These changes can lead to life-threatening complications. For the fetus, preeclampsia can result in abnormal growth and prematurity; for the mother, it can cause extensive damage to internal organs such as the kidneys, liver, lungs and brain.
In the most severe cases, the mother may develop liver or kidney failure, bleeding disorders or seizures that can lead to coma and death. Once seizures occur, the condition is referred to as eclampsia.
Women who are younger than 20, older than 40, overweight or carrying twins or triplets are more likely to develop preeclampsia, as are those with certain medical conditions, such as diabetes and high blood pressure.
The exact cause of preeclampsia is not known. At one time, it was believed that poisonous toxins in the pregnant woman's blood were responsible (hence, the condition was called "toxemia of pregnancy"). However, no such toxins have been identified.
Simple blood pressure measurements and urinalyses provide the earliest and best clues that preeclampsia is developing. A diagnosis is made when significant elevations in blood pressure are detected after the 20th week of pregnancy and are accompanied by evidence of protein in the urine.
The "and" is important because not all pregnant women with high blood pressure have preeclampsia. Some suffer from chronic hypertension--their blood pressure was elevated before they became pregnant. (If their blood pressure was not measured before they became pregnant, it may be difficult at first to determine if they have preeclampsia.)
