Preeclampsia is a complication of pregnancy. With preeclampsia, you might have high blood pressure, high levels of protein in urine that indicate kidney damage (proteinuria), or other signs of organ damage. Preeclampsia usually begins after 20 weeks of pregnancy in women whose blood pressure had previously been in the standard range.

Left untreated, preeclampsia can lead to serious — even fatal — complications for both the mother and baby.

Early delivery of the baby is often recommended. The timing of delivery depends on how severe the preeclampsia is and how many weeks pregnant you are. Before delivery, preeclampsia treatment includes careful monitoring and medications to lower blood pressure and manage complications.

Preeclampsia may develop after delivery of a baby, a condition known as postpartum preeclampsia.

The defining feature of preeclampsia is high blood pressure, proteinuria, or other signs of damage to the kidneys or other organs. You may have no noticeable symptoms. The first signs of preeclampsia are often detected during routine prenatal visits with a health care provider.

Along with high blood pressure, preeclampsia signs and symptoms may include:

• Excess protein in urine (proteinuria) or other signs of kidney problems
• Decreased levels of platelets in blood (thrombocytopenia)
• Increased liver enzymes that indicate liver problems
• Severe headaches
• Changes in vision, including temporary loss of vision, blurred vision or light sensitivity
• Shortness of breath, caused by fluid in the lungs
• Pain in the upper belly, usually under the ribs on the right side
• Nausea or vomiting

Weight gain and swelling (edema) are typical during healthy pregnancies. However, sudden weight gain or a sudden appearance of edema — particularly in your face and hands — may be a sign of preeclampsia.

Make sure you attend your prenatal visits so that your health care provider can monitor your blood pressure. Contact your provider immediately or go to an emergency room if you have severe headaches, blurred vision or other visual disturbances, severe belly pain, or severe shortness of breath.

Because headaches, nausea, and aches and pains are common pregnancy complaints, it's difficult to know when new symptoms are simply part of being pregnant and when they may indicate a serious problem — especially if it's your first pregnancy. If you're concerned about your symptoms, contact your doctor.

The exact cause of preeclampsia likely involves several factors. Experts believe it begins in the placenta — the organ that nourishes the fetus throughout pregnancy. Early in a pregnancy, new blood vessels develop and evolve to supply oxygen and nutrients to the placenta.

In women with preeclampsia, these blood vessels don't seem to develop or work properly. Problems with how well blood circulates in the placenta may lead to the irregular regulation of blood pressure in the mother.

Other high blood pressure disorders during pregnancy

Preeclampsia is one high blood pressure (hypertension) disorder that can occur during pregnancy. Other disorders can happen, too:

• Gestational hypertension is high blood pressure that begins after 20 weeks without problems in the kidneys or other organs. Some women with gestational hypertension may develop preeclampsia.
• Chronic hypertension is high blood pressure that was present before pregnancy or that occurs before 20 weeks of pregnancy. High blood pressure that continues more than three months after a pregnancy also is called chronic hypertension.
• Chronic hypertension with superimposed preeclampsia occurs in women diagnosed with chronic high blood pressure before pregnancy, who then develop worsening high blood pressure and protein in the urine or other health complications during pregnancy.

Conditions that are linked to a higher risk of preeclampsia include:

• Preeclampsia in a previous pregnancy
• Being pregnant with more than one baby
• Chronic high blood pressure (hypertension)
• Type 1 or type 2 diabetes before pregnancy
• Kidney disease
• Autoimmune disorders
• Use of in vitro fertilization

Conditions that are associated with a moderate risk of developing preeclampsia include:

• First pregnancy with current partner
• Obesity
• Family history of preeclampsia
• Maternal age of 35 or older
• Complications in a previous pregnancy
• More than 10 years since previous pregnancy

Other risk factors

Several studies have shown a greater risk of preeclampsia among Black women compared with other women. There's also some evidence of an increased risk among indigenous women in North America.

A growing body of evidence suggests that these differences in risk may not necessarily be based on biology. A greater risk may be related to inequities in access to prenatal care and health care in general, as well as social inequities and chronic stressors that affect health and well-being.

Lower income also is associated with a greater risk of preeclampsia likely because of access to health care and social factors affecting health.

For the purposes of making decisions about prevention strategies, a Black woman or a woman with a low income has a moderately increased risk of developing preeclampsia.

Complications of preeclampsia may include:

• Fetal growth restriction. Preeclampsia affects the arteries carrying blood to the placenta. If the placenta doesn't get enough blood, the baby may receive inadequate blood and oxygen and fewer nutrients. This can lead to slow growth known as fetal growth restriction.
• Preterm birth. Preeclampsia may lead to an unplanned preterm birth — delivery before 37 weeks. Also, planned preterm birth is a primary treatment for preeclampsia. A baby born prematurely has increased risk of breathing and feeding difficulties, vision or hearing problems, developmental delays, and cerebral palsy. Treatments before preterm delivery may decrease some risks.
• Placental abruption. Preeclampsia increases your risk of placental abruption. With this condition, the placenta separates from the inner wall of the uterus before delivery. Severe abruption can cause heavy bleeding, which can be life-threatening for both the mother and baby.

• HELLP syndrome. HELLP stands for hemolysis (the destruction of red blood cells), elevated liver enzymes and low platelet count. This severe form of preeclampsia affects several organ systems. HELLP syndrome is life-threatening to the mother and baby, and it may cause lifelong health problems for the mother.

  Signs and symptoms include nausea and vomiting, headache, upper right belly pain, and a general feeling of illness or being unwell. Sometimes, it develops suddenly, even before high blood pressure is detected. It also may develop without any symptoms.

• Eclampsia. Eclampsia is the onset of seizures or coma with signs or symptoms of preeclampsia. It is very difficult to predict whether a patient with preeclampsia will develop eclampsia. Eclampsia can happen without any previously observed signs or symptoms of preeclampsia.

  Signs and symptoms that may appear before seizures include severe headaches, vision problems, mental confusion or altered behaviors. But, there are often no symptoms or warning signs. Eclampsia may occur before, during or after delivery.

• Other organ damage. Preeclampsia may result in damage to the kidneys, liver, lung, heart, or eyes, and may cause a stroke or other brain injury. The amount of injury to other organs depends on how severe the preeclampsia is.
• Cardiovascular disease. Having preeclampsia may increase your risk of future heart and blood vessel (cardiovascular) disease. The risk is even greater if you've had preeclampsia more than once or you've had a preterm delivery.

Medication

The best clinical evidence for prevention of preeclampsia is the use of low-dose aspirin. Your primary care provider may recommend taking an 81-milligram aspirin tablet daily after 12 weeks of pregnancy if you have one high-risk factor for preeclampsia or more than one moderate-risk factor.

It's important that you talk with your provider before taking any medications, vitamins or supplements to make sure it's safe for you.

Lifestyle and healthy choices

Before you become pregnant, especially if you've had preeclampsia before, it's a good idea to be as healthy as you can be. Talk to your provider about managing any conditions that increase the risk of preeclampsia.

A diagnosis of preeclampsia happens if you have high blood pressure after 20 weeks of pregnancy and at least one of the following findings:

• Protein in your urine (proteinuria), indicating an impaired kidney
• Other signs of kidney problems
• A low blood platelet count
• Elevated liver enzymes showing an impaired liver
• Fluid in the lungs (pulmonary edema)
• New headaches that don't go away after taking pain medication
• New vision disturbances

High blood pressure

A blood pressure reading has two numbers. The first number is the systolic pressure, a measure of blood pressure when the heart is contracting. The second number is the diastolic pressure, a measure of blood pressure when the heart is relaxed.

In pregnancy, high blood pressure is diagnosed if the systolic pressure is 140 millimeters of mercury (mm Hg) or higher or if the diastolic pressure is 90 mm Hg or higher.

A number of factors can affect your blood pressure. If you have a high blood pressure reading during an appointment, your health care provider will likely take a second reading four hours later to confirm a diagnosis of high blood pressure.

Additional tests

If you have high blood pressure, your health care provider will order additional tests to check for other signs of preeclampsia:

• Blood tests. A blood sample analyzed in a lab can show how well the liver and kidneys are working. Blood tests can also measure the amount of blood platelets, the cells that help blood clot.
• Urine analysis. Your health care provider will ask you for a 24-hour urine sample or a single urine sample to determine how well the kidneys are working.
• Fetal ultrasound. Your primary care provider will likely recommend close monitoring of your baby's growth, typically through ultrasound. The images of your baby created during the ultrasound exam allow for estimates of the baby's weight and the amount of fluid in the uterus (amniotic fluid).
• Nonstress test or biophysical profile. A nonstress test is a simple procedure that checks how your baby's heart rate reacts when your baby moves. A biophysical profile uses an ultrasound to measure your baby's breathing, muscle tone, movement and the volume of amniotic fluid in your uterus.

The primary treatment for preeclampsia is either to deliver the baby or manage the condition until the best time to deliver the baby. This decision with your health care provider will depend on the severity of preeclampsia, the gestational age of your baby, and the overall health of you and your baby.

If preeclampsia isn't severe, you may have frequent provider visits to monitor your blood pressure, any changes in signs or symptoms, and the health of your baby. You'll likely be asked to check your blood pressure daily at home.

Treatment of severe preeclampsia

Severe preeclampsia requires that you be in the hospital to monitor your blood pressure and possible complications. Your health care provider will frequently monitor the growth and well-being of your baby.

Medications to treat severe preeclampsia usually include:

• Antihypertensive drugs to lower blood pressure
• Anticonvulsant medication, such as magnesium sulfate, to prevent seizures
• Corticosteroids to promote development of your baby's lungs before delivery

Delivery

If you have preeclampsia that isn't severe, your health care provider may recommend preterm delivery after 37 weeks. If you have severe preeclampsia, your health care provider will likely recommend delivery before 37 weeks, depending on the severity of complications and the health and readiness of the baby.

The method of delivery — vaginal or cesarean — depends on the severity of disease, gestational age of the baby and other considerations you would discuss with your health care provider.

After delivery

You need to be closely monitored for high blood pressure and other signs of preeclampsia after delivery. Before you go home, you'll be instructed when to seek medical care if you have signs of postpartum preeclampsia, such as severe headaches, vision changes, severe belly pain, nausea and vomiting.

Discovering that you have a potentially serious pregnancy complication can be frightening.

If you're diagnosed with preeclampsia late in your pregnancy, you may be surprised to learn that immediate delivery may be recommended. If you're diagnosed earlier in your pregnancy, you may be concerned about monitoring signs and symptoms at home and keeping more frequent appointments with your primary care provider.

It may help to learn more about your condition. In addition to talking to your provider, do some research. Make sure you understand when to call your provider and how to monitor signs and symptoms.

Preeclampsia is often diagnosed during a regularly scheduled prenatal appointment. If your primary care provider recommends certain tests for a preeclampsia diagnosis, you may also be discussing some of the following questions:

• Did you have preeclampsia or other complications in a previous pregnancy?
• If you're having symptoms of preeclampsia, when did they begin?
• Has anything improved the symptoms or made them worse?
• Have you made any recent changes to your medications, vitamins or dietary supplements?

After a diagnosis of preeclampsia and at follow-up appointments, you might ask the following questions:

• How can I make sure I'm doing blood pressure readings correctly at home?
• How often should I check my blood pressure at home?
• What blood pressure reading should I consider high?
• When should I call the clinic?
• When should I get emergency care?
• How will we monitor my baby's health?
• When should I schedule my next appointment?
• How will we decide on the right time for delivery?
• What are the benefits and risks of delaying delivery?
• What care might my baby need after a preterm delivery?