Originally published by Harvard Health.
What Is It?
Preeclampsia is a condition that occurs only during pregnancy, and usually only after the 20th week. A woman with preeclampsia develops high blood pressure and protein in her urine, and she often has swelling (edema) of the legs, hands, face, or entire body. When preeclampsia becomes severe, it can cause dangerous complications for the mother and the fetus. One of these complications is eclampsia, the name for seizures that are associated with severe preeclampsia.
Experts are still not entirely sure what causes preeclampsia, but recent research has provided some good clues. The best hypothesis is that preeclampsia occurs when the placenta does not anchor itself as deeply as expected within the wall of the uterus during the first trimester. What causes this abnormal anchoring is unclear, but it may be influenced by the mother’s or father’s genes or the mother’s immune system, and medical conditions the mother may have, such as diabetes or high blood pressure.
Regardless of its cause, early abnormalities in placental formation lead to changes that later affect blood vessels and other organs. Arteries throughout the body can tighten (become narrower), raising blood pressure. They can also become “leaky,” allowing protein or fluid to seep through their walls, which causes tissues to swell. In preeclampsia, changes in arteries decrease the blood supply to the fetus and placenta, and to the woman’s kidneys, liver, eyes, brain, and other organs.
In parts of the world with more limited medical care, preeclampsia and eclampsia cause many women to die during pregnancy. Fortunately, with appropriate prenatal care and monitoring, most women with preeclampsia and eclampsia and their babies survive just fine.
Eclampsia and, especially, death from preeclampsia are very rare in well-resourced countries like the United States. However, even with the best care, preeclampsia is a leading cause of illness for mothers and newborns. The following conditions increase the chance that a woman will develop preeclampsia:
- Chronic (long-lasting) high blood pressure
- Kidney disease
- Being under 15 years old or over 35 years old
- It being the woman’s first pregnancy
- Having had preeclampsia in a previous pregnancy
- Multiple gestations: twins, triplets, or a greater number of multiples (These pregnancies have more placental tissue. This suggests that the placenta or things it produces may play a role.)
- Certain autoimmune conditions, including antiphospholipid antibody syndrome and some autoimmune arthritis conditions
- African-American or Hispanic ethnicity
- Having a sister, mother, or daughter who had preeclampsia or high blood pressure during pregnancy
- Having a male partner whose previous partner had preeclampsia (this suggests that the father’s genetic material, passed to the fetus and its placenta, may play a role)
- Having a male partner with whom you were sexually active for only a short length of time prior to becoming pregnant (this may be due to a change in the way a woman’s immune system reacts to genes from the father after repeated exposure to his semen)
A woman with mild preeclampsia may not notice any symptoms, or she may have only mild swelling of the hands or feet. However, most pregnant women have some degree of swelling of the feet. So not all swelling indicates preeclampsia.
Symptoms of severe preeclampsia can include:
- Visual changes
- Nausea and abdominal pain, usually in the upper abdomen
- Difficulty breathing
Eclampsia causes seizures, which are jerking movements of the arms and legs. During a seizure, a woman is likely to lose consciousness, and she may lose control of her bladder or bowels.
Because preeclampsia doesn’t always cause noticeable symptoms, it is crucial that all pregnant women see a health care professional regularly during pregnancy for prenatal care. This gives you the best chance of having preeclampsia diagnosed and managed before it becomes severe. Your doctor or midwife will measure your blood pressure and test your urine for protein at each prenatal visit because abnormal results are the earliest, most common signs of preeclampsia.
Preeclampsia can be especially difficult to detect in women who have a history of high blood pressure (hypertension) before pregnancy. One in four women with high blood pressure develops preeclampsia during pregnancy, so it is essential that these women be monitored closely for changes in blood pressure and for protein in the urine.
Your doctor or midwife will diagnose preeclampsia depending on your symptoms and the results of certain tests. There is no one blood test currently available to determine if someone does or does not have preeclampsia. Since a simple blood test is not available, here is how the diagnosis is determined:
- Mild preeclampsia is characterized by the following:
- Blood pressure of 140/90 or above
- Swelling, particularly of the arms, hands, or face that is reflected in greater than expected weight gain, which is a result of retaining fluid. (Swelling in the ankle area is considered normal during pregnancy.)
- Protein in the urine
- Severe preeclampsia is characterized by:
- Blood pressure of 160/110 or higher in more than one reading separated by at least six hours
- A 24 hour urine collection that has more than 5 grams of protein
- Symptoms such as severe headache, changes in vision, reduced urine output, abdominal pain, fluid in the lungs and pelvic pain
- Signs of the “HELLP” syndrome, which means the liver and blood-clotting systems are not functioning properly. HELLP stands for Hemolysis (damaged red blood cells), Elevated Liver enzymes (indicating ongoing liver cell damage) and Low Platelets (cells that help the blood to clot). It occurs in about 10% of patients with severe preeclampsia.
- Eclampsia is diagnosed when a woman with preeclampsia has seizures. These seizures usually happen in women who have severe preeclampsia, though they can occur with preeclampsia. Eclampsia also can happen soon after a woman gives birth. Approximately 30% to 50% of patients with eclampsia also have the HELLP syndrome.
Preeclampsia can begin as early as the 20th week of pregnancy, or very rarely even earlier. But it is more likely to develop during the last three months of pregnancy. In fact, the majority of cases are diagnosed in the last weeks of pregnancy. When a diagnosis of preeclampsia is made long before delivery, the pregnancy usually can be managed with a combination of bedrest and careful observation. Because preeclampsia can quickly worsen, doctors will often recommend that women with preeclampsia be admitted to the hospital for such rest and observation. If the condition worsens and threatens the health of the mother, delivery is usually recommended. Delivery will also be recommended as a pregnancy approaches its due date, to prevent worsening preeclampsia. In most cases preeclampsia goes away after delivery, although, as noted above, for reasons that are poorly understood, some cases of preeclampsia occur after delivery.
Currently there are few recommendations that can be made to prevent preeclampsia. Because certain health problems (diabetes, high blood pressure, lupus) are associated with preeclampsia, women should be in the best health possible before becoming pregnant. This includes not being overweight and gaining the appropriate weight once pregnant. Some experts suspect that low-dose aspirin may provide slight protection to women who are at especially high risk of preeclampsia (for example, women who have had severe or early preeclampsia with a previous pregnancy. However, any benefit of aspirin treatment is small, and it has not been shown to work for women at average risk.
Getting prenatal care is one of the most important things you can do to keep yourself health during pregnancy. Preeclampsia is one of the many things your doctor or midwife will be on the lookout for.
In women whose preeclampsia is getting markedly worse, magnesium sulfate is given to prevent eclamptic seizures. Magnesium sulfate may be given either through an intravenous line or as an injection.
The only cure for preeclampsia and eclampsia is to deliver the baby. (Actually, the cure is the delivery of the placenta, but one can’t deliver the placenta without delivering the baby.) How you proceed depends on the severity of your preeclampsia.
- Mild preeclampsia. The goal of treating mild preeclampsia is to delay delivery until the fetus is mature enough to live outside the womb. You most likely will be put on bedrest and your doctor or midwife will monitor your blood pressure, weight, urine protein, liver enzymes, kidney function, and the clotting factors in your blood. Your provider also will monitor the well-being and growth of your fetus. Some women need to be hospitalized for adequate treatment and monitoring, while others can remain in bed at home. If you are not hospitalized, you will need to be seen by your health care professional frequently.
- Severe preeclampsia. The overall goal is to prevent serious consequences to the mother’s and fetus’ health, including eclampsia, stillbirth, and liver and kidney failure. Women with severe preeclampsia are carefully monitored, and high blood pressure is treated with medication. If the condition of the mother or baby gets worse, the baby may need to be delivered early. If the pregnancy reaches a gestational age at which the consequences of premature delivery are outweighed by the risks of continuing the pregnancy (generally about 32 to 34 weeks of gestation), an obstetrician may also recommend delivery. Your physical health and well-being will begin returning to normal after the baby is delivered.
- Eclampsia. Magnesium sulfate is used to prevent eclamptic seizures in women with preeclampsia at highest risk for them. When eclamptic seizures occur, magnesium sulfate will be started (for those not on it already) or given again (for those in whom seizures have occurred in spite of initial treatment) in an effort to prevent recurrent seizures. Other medications, such as lorazepam (Ativan), may be used to stop (“break”) a seizure in progress.
When To Call a Professional
You should schedule your first prenatal care visit with a health care professional as soon as you know you are pregnant. If you have swelling, severe headache, changes in vision, or other symptoms of preeclampsia, contact your doctor or midwife immediately.
The outlook for full recovery from preeclampsia is very good. Most women begin to improve within one to two days after delivery, and blood pressure returns to their normal pre-pregnancy range within the next one to six weeks in almost all cases.
About one of every five women with preeclampsia during a first pregnancy will have preeclampsia during a second pregnancy. Those with early or severe preeclampsia, or who have other medical conditions such as high blood pressure or diabetes, are at greatest risk for recurrence.
Women who have had preeclampsia are at risk for developing high blood pressure and other cardiovascular diseases later in life. You should let your primary care provider know if you have had preeclampsia. Although at present no specific treatments are recommended for women who have had preeclampsia to prevent later problems, it is prudent to adopt a healthy lifestyle. This includes:
- Maintaining a healthy weight
- Exercising regularly and being physically active
- Eating a well-balanced diet
- Not smoking
- Using alcohol in moderation
American Academy of Family Physicians (AAFP)
P.O. Box 11210
Shawnee Mission, KS 66207-1210
American College of Obstetricians and Gynecologists
P.O. Box 96920
Washington, DC 20090-6920