Preeclampsia is a condition characterized by the development of elevated blood pressure, swelling and proteinuria (protein in the urine) during pregnancy. A common complication of pregnancy, the condition affects the expectant mother and her fetus.

Also known as toxemia or pregnancy-induced hypertension (PIH), preeclampsia is a condition that occurs only during pregnancy and the postpartum period. Although it may occur at any time during pregnancy, delivery and up to six weeks postpartum, it most often occurs after the 20^th week of pregnancy.

Blood pressure is the measure of the force of the blood pushing against the walls of the arteries (the blood vessels that carry blood from the heart to the rest of the body). The higher the measurement, the higher the workload and strain on the heart. Blood pressure is measured by correlating it to the rhythmic contractions of the heart. Blood pressure measured during the heart’s contraction phase (systole) is known as systolic pressure. Blood pressure measured during the heart’s relaxation phase (diastole) is known as diastolic pressure. The measurements are then expressed as a ratio of systolic pressure over diastolic pressure.

According to the American Heart Association, a blood pressure reading less than 120/80 millimeters of mercury (mm Hg) is considered normal. For pregnant women, blood pressure readings below 130/85 mm Hg are considered normal. A reading of 140/90 mm Hg or higher is considered high, or above the normal range. Obstetrician-gynecologists (ObGyns) usually monitor blood pressure closely during pregnancy because high blood pressure (hypertension) can develop rapidly, especially during the last three months.

Preeclampsia does not appear to cause chronic high blood pressure. It is usually resolved within 48 hours of delivery. In some cases, it may take a few days or weeks for blood pressure to return to normal.

In addition to high blood pressure, women with preeclampsia also develop proteinuria (the presence of abnormally high levels of protein in the urine).

By itself, high blood pressure is not preeclampsia. In addition, proteinuria alone does not necessarily indicate preeclampsia. However, when a woman develops high blood pressure her ObGyn will closely monitor her for changes that could indicate preeclampsia.  

Patients may also have edema (swelling caused by the buildup of fluid in the tissues). Although some degree of swelling is normal during pregnancy, the swelling associated with preeclampsia is more severe.

Swelling during pregnancy should be considered a concern if it does not decrease after resting, if it is very noticeable in the face or hands, or if there is a rapid weight gain of more than 5 pounds in a week.

According to the Preeclampsia Foundation, preeclampsia affects at least 5 to 8 percent of all pregnancies. It may develop gradually or occur suddenly, possibly flaring up in a matter of hours. Most women with preeclampsia deliver healthy babies but the condition can cause serious complications for the mother and her fetus. Preeclampsia may be described as mild or severe. In general, the more serious a woman’s preeclampsia and the earlier it occurs, the greater the risk of complications.

Left untreated, preeclampsia can progress into two serious conditions:

• HELLP syndrome. HELLP stands for:
  
  
• Hemolysis (the destruction of red blood cells)
• Elevated liver enzymes
• Low platelet count
  
  
According to the Preeclampsia Foundation, HELLP syndrome occurs in 4 to 12 percent of women with preeclampsia. It can lead to liver failure and coagulation (blood clotting) disorders, and poses a high risk of death for the mother and her fetus. It is especially dangerous because it can occur before the expectant mother exhibits any sign or symptom of preeclampsia. The condition is frequently mistaken for influenza or gallbladder disorders.


• Eclampsia. This rare condition is characterized by seizures caused by preeclampsia. It can develop when the signs and symptoms of preeclampsia are not controlled. A life-threatening condition, eclampsia can cause permanent damage to the expectant mother’s vital organs including the brain, liver and kidneys. Left untreated, the condition can lead to coma, brain damage or death of the mother or her fetus.

Preeclampsia was given its name because it was first defined as the condition that led to eclampsia. However, physicians now realize that the progression from one condition to the other is not inevitable.

The elevation in blood pressure increases the expectant mother’s risk of numerous other conditions including stroke and pulmonary edema (fluid in the lungs). Women who experience high blood pressure during pregnancy also appear to be at greater risk of stroke, heart and kidney disease later in life, according to new findings.

Preeclampsia also increases the risk of a rare condition called placental abruption (the placenta separating from the inner wall of the uterus before delivery, also called placental abruptio). Severe placental abruption can lead to heavy bleeding, which can cause the mother to go into shock. Like eclampsia, placental abruption is life-threatening for the mother and her fetus.

Potential complications for the fetus include:

• Premature birth. Reduced blood flow to the placenta may cause the birth of a baby weighing less than 5.5 pounds (2.5 kilograms). Infants being born prematurely as the result of preeclampsia may face a variety of life challenges, including learning disabilities, cerebral palsy, epilepsy, blindness and deafness.
  
  
• Intrauterine growth retardation. Reduced blood flow to the placenta decreases the supply of food to the baby, possibly resulting in starvation. As a result, the fetus may experience a decreased rate of growth and development.
  
  
• Acidosis. Reduced blood flow to the placenta results in less oxygen reaching the fetus. If the fetus comes to a point where there is no further reserve of oxygen (the placenta detaches or dies), the fetus will extract the energy it needs from its fuel supply without oxygen. This process produces lactic acid, a toxic waste product. If excessive lactic acid builds up, the fetus will develop acidosis and become unconscious.

Although preeclampsia may lead to the development of many complications, it is usually detected early during routine prenatal visits. As a result, most problems can be prevented. According to the National Institutes of Health (NIH), preeclampsia rarely causes maternal death in the United States. However, the rate of fetal and perinatal death is high. According to the Preeclampsia Foundation, more than 1,200 babies die as the result of preeclampsia each year in the United States. This rate generally decreases as the fetus matures in the womb. Worldwide, approximately 76,000 maternal and fetal deaths are caused by preeclampsia every year.