Topic Overview

What is pre-eclampsia?

Pre-eclampsia is new high blood pressure after 20 weeks of pregnancy. It usually goes away after you give birth.

Not all high blood pressure is pre-eclampsia. In some women, blood pressure goes up very high in the second or third trimester. This is sometimes called gestational hypertension, and it can lead to pre-eclampsia .

Pre-eclampsia can be dangerous for the mother and baby. It can keep the baby from getting enough blood and oxygen. It also can harm the mother's liver, kidneys, and brain. Women with very bad pre-eclampsia can have dangerous seizures. This is called eclampsia.

What causes pre-eclampsia?

Experts don't know the exact cause.

Pre-eclampsia seems to start because the placenta doesn't grow the usual network of blood vessels deep in the wall of the uterus. This leads to poor blood flow in the placenta.

If your mother had pre-eclampsia while she was pregnant with you, you have a higher chance of getting it during pregnancy. You also have a higher chance of getting it if the mother of your baby's father had pre-eclampsia.

Already having high blood pressure when you get pregnant raises your chance of getting pre-eclampsia.

What are the symptoms?

Mild pre-eclampsia usually doesn't cause symptoms.

But pre-eclampsia can cause rapid weight gain and sudden swelling of the hands and face.

Severe pre-eclampsia causes symptoms such as a very bad headache and trouble seeing and breathing. It also can cause belly pain and decreased urination.

How is pre-eclampsia diagnosed?

Pre-eclampsia is usually found during a prenatal visit.

This is one reason why it's so important to go to all of your prenatal visits. You need to have your blood pressure checked often. During these visits, your blood pressure is measured. A sudden increase in blood pressure often is the first sign of a problem.

You also will have a urine test to look for protein, another sign of pre-eclampsia.

If you have high blood pressure, tell your doctor right away if you have a headache or belly pain. These signs of pre-eclampsia can occur before protein shows up in your urine.

How is it treated?

The only cure for pre-eclampsia is having the baby.

You may get medicines to lower your blood pressure and to prevent seizures.

You also may get medicine to help your baby's lungs get ready for birth.

Your doctor will try to deliver your baby when the baby has grown enough to be ready for birth. But sometimes a baby has to be delivered early to protect the health of the mother or the baby. If this happens, your baby will get special care for premature babies.

Frequently Asked Questions

Learning about pre-eclampsia:

Being diagnosed:

Getting treatment:

Ongoing concerns:

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Experts don't know the exact cause of pre-eclampsia.

But it may start with a poorly developed placenta that doesn't circulate blood normally. What causes this placenta problem isn't yet clear. Experts also don't know why the mother's body then develops high blood pressure.

Immune system response

Pre-eclampsia occurs most often in women who are pregnant for the first time and in women who have been pregnant before but now have a first pregnancy with a different man.

Exposure to an antigen from the father (in the growing placenta or fetus, for example) may trigger an immune response in the woman's body. This immune response—the body's way of fighting infection—may result in narrowing of the blood vessels throughout the body, causing higher blood pressure and other problems.


Although you may have other symptoms, you will not be diagnosed with pre-eclampsia unless you also have one or both of the following:

  • Your blood pressure is high.
  • A urine test shows that you have too much protein in your urine.
  • You have other problems related to pre-eclampsia.

Other symptoms of mild pre-eclampsia may include:

  • Swelling of the hands and face that doesn't go away during the day. (If you have no other symptoms of pre-eclampsia, this swelling is probably a sign of normal pregnancy.)
  • Rapid weight gain—more than 1 kg (2 lb) a week or 3 kg (6 lb) a month.
  • Bleeding from a cut or injury that lasts longer than usual.

Severe pre-eclampsia

In severe pre-eclampsia, systolic blood pressure is over 160, or diastolic blood pressure is over 110, or both.

As blood circulation to the organs decreases, more severe symptoms can develop, including:

  • A severe headache that will not go away with medicine such as acetaminophen.
  • Blurred or dimming vision, spots in the visual field, or periods of blindness.
  • Decreased urination—less than 500 mL (2 cups) in 24 hours.
  • Lasting belly pain or tenderness, especially on the upper right side.
  • Problems breathing, especially when lying flat.
  • HELLP syndrome. This is a life-threatening liver disorder. It is usually related to pre-eclampsia. Get emergency medical treatment if you have several symptoms of HELLP syndrome, such as headaches, vision problems, fatigue, or belly pain.


When pre-eclampsia leads to seizures , it is called eclampsia .

Eclampsia is life-threatening for both a mother and her baby. During a seizure, the oxygen supply to the baby is drastically reduced.

Call 911 any time a pregnant woman has a seizure.

What Happens

Pre-eclampsia can be mild or severe. It may get worse gradually or rapidly. It affects your blood pressure, placenta, liver, blood, kidneys, and brain.

It's very important to get treatment, because both you and your baby could suffer life-threatening problems involving your:

  • Blood pressure. The blood vessels increase their resistance against blood flow, increasing blood pressure. Very high blood pressure keeps your baby from getting enough blood and oxygen. Also, blood volume doesn't increase as much as it should during pregnancy. This can affect the baby's growth and well-being.
  • Placenta. The blood vessels of the placenta don't grow deep into the uterus as they should. And they don't widen as they normally would. This makes them unable to provide normal blood flow to the baby.
  • Liver. Poor blood flow to the mother's liver can cause liver damage. Liver impairment is related to the life-threatening HELLP syndrome, which requires emergency medical treatment.
  • Kidneys. When affected by pre-eclampsia, the kidneys can't work as well as they should to remove waste and extra water.
  • Brain. Vision impairment, persistent headaches, and seizures (eclampsia) can develop. Eclampsia can lead to maternal coma and fetal and maternal death. This is why women with pre-eclampsia are often given medicine to prevent eclampsia.
  • Blood. Low platelet levels in the blood are common with pre-eclampsia. In rare cases, a potentially life-threatening blood-clotting and bleeding problem develops along with severe pre-eclampsia. footnote 1 This condition is called disseminated intravascular coagulation (DIC). After delivery, DIC goes away. In the meantime, you may be given a medicine (clotting factor), blood transfusion, or platelet transfusion.

Delivery of the baby and placenta is the only "cure" for pre-eclampsia. If your condition becomes dangerous enough that delivery is necessary but you don't go into labour, your doctor will induce labour or deliver the baby with surgery (caesarean section).

Unless you have chronic high blood pressure, your blood pressure should return to normal in a few days or weeks. In severe cases, this can take 6 or more weeks.

After having pre-eclampsia, you have a higher-than-average risk of heart disease, stroke, and kidney disease. This may be because the same things that cause pre-eclampsia also cause heart and kidney disease. To protect your health, work with your doctor on living a heart-healthy lifestyle and getting the checkups you need.

The infant

The earlier in the pregnancy that pre-eclampsia begins and the more severe it becomes, the greater the risk of preterm birth, which can cause problems for the newborn.

An infant born before 37 weeks may have difficulty breathing because of immature lungs ( respiratory distress syndrome ).

A newborn affected by pre-eclampsia may also be smaller than normal. This is because of inadequate nutrition from poor blood flow through the placenta.

What Increases Your Risk

Risk factors (things that increase your risk) for pre-eclampsia include:

  • Chronic (ongoing) high blood pressure, chronic kidney disease, or diabetes.
  • High blood pressure in a past pregnancy, especially before week 34.
  • Personal history of pre-eclampsia.
  • Family history of pre-eclampsia.
  • Being very overweight at the time of conception.
  • Being pregnant with more than one baby (such as twins or triplets).
  • First pregnancy ever or first-time pregnancy with current partner.
  • Age younger than 21 or older than 35.

When To Call a Doctor

Someone must call 911 or other emergency services immediately if you are having a seizure ( eclampsia ). Eclampsia can lead to a coma. It is life-threatening to both you and your baby.

If you are pregnant and have pre-eclampsia, your family and friends should know how to help during a seizure.

Seek medical care immediately if you are pregnant and begin to have symptoms of pre-eclampsia, such as:

  • Blurred vision or other vision problems.
  • Frequent headaches that are becoming worse or a persistent headache that does not respond to non-prescription pain medicine.
  • Pain or tenderness in your belly, especially in the upper right section.
  • Weight gain of 1 kg (2 lb) or more over a 24-hour period.
  • Shoulder, neck, and other upper body pain (this pain starts in the liver).

If you have mild high blood pressure or mild pre-eclampsia, you may not have any symptoms. It is important to see a health professional regularly throughout your pregnancy.

Symptoms such as heartburn or swelling in the legs and feet are normal during pregnancy. They usually aren't symptoms of pre-eclampsia. You can discuss these symptoms with your doctor or midwife at your next scheduled prenatal visit. But if swelling occurs along with other symptoms of pre-eclampsia, contact your doctor right away.

Who to see

Your family doctor , general practitioner , or midwife can treat high blood pressure and pre-eclampsia during pregnancy. You may be referred to an obstetrician or a perinatologist .

To prepare for your appointment, see the topic Making the Most of Your Appointment.

Examinations and Tests

Pre-eclampsia is usually found during regular prenatal checkups.

Routine prenatal tests

Certain tests are given at each prenatal visit to check for pre-eclampsia. These include a:

  • Blood pressure reading. Blood pressure is always monitored closely during pregnancy.
  • Urine test to check for too much protein in the urine. This is a sign of kidney damage caused by pre-eclampsia.
  • Weight measurement. Rapid weight gain can be a sign of pre-eclampsia.

Tests for women considered high-risk for pre-eclampsia

Other tests may also be used to check for signs of pre-eclampsia, including:

  • Blood tests to check for problems such as HELLP syndrome and kidney damage. (Too much uric acid in the blood is often the earliest sign of pre-eclampsia.)
  • Creatinine clearance test to check kidney function. This requires both a blood sample and a 24-hour urine collection.
  • 24-hour urine collection test to check protein in the urine.

Tests for women who have pre-eclampsia

If results from one or more of the above tests suggest that you have pre-eclampsia, you and your baby will be closely monitored for the rest of your pregnancy.

Testing is more frequent and extensive when pre-eclampsia is severe and the pregnancy is far from full-term (less than 36 weeks).

You may have a physical examination to check for signs that pre-eclampsia is getting worse.

You may also have:

  • Blood tests to check for blood abnormalities and kidney damage.
  • A creatinine clearance test.

Tests for women who have eclampsia

If you have a seizure (eclampsia), one or more of the following tests may be done after delivery:

Tests for the baby

If you get pre-eclampsia, the baby's health also will be closely watched. The more severe your condition, the more often you'll need testing, ranging from once a week to daily.

Tests commonly used include:

Less often, amniocentesis is used to check fetal well-being if preterm delivery is being considered. The test shows whether the baby's lungs are mature enough for birth.

Treatment Overview

Mild pre-eclampsia

For mild pre-eclampsia that is not rapidly getting worse, you may only have to reduce your level of activity, monitor how you feel, and have frequent office visits and testing.

Moderate to severe pre-eclampsia

For moderate or severe pre-eclampsia, or for pre-eclampsia that is rapidly getting worse, you may need to go to the hospital for expectant management. This typically includes bedrest, medicine, and close monitoring of you and your baby.

Severe pre-eclampsia or an eclamptic seizure is treated with magnesium sulfate. This medicine can stop a seizure and can prevent seizures. If you are near delivery or have severe pre-eclampsia, your doctor will plan to deliver your baby as soon as possible.

Life-threatening pre-eclampsia

If your condition becomes life-threatening to you or your baby, the only treatment options are magnesium sulfate to prevent seizures and delivering the baby.

If you are less than 34 weeks pregnant and a 24- to 48-hour delay is possible, you will likely be given antenatal corticosteroids to speed up the baby's lung development before delivery.


A vaginal delivery is usually safest for the mother. It is tried first if she and the baby are both stable.

If pre-eclampsia is rapidly getting worse or fetal monitoring suggests that the baby cannot safely handle labour contractions, a caesarean section (C-section) delivery is needed.

After childbirth

If you have moderate to severe pre-eclampsia, your risk of seizures (eclampsia) continues for the first 24 to 48 hours after childbirth. (In very rare cases, seizures are reported later in the postpartum period.) So you may continue magnesium sulfate for 24 hours after delivery. footnote 1

Unless you have chronic high blood pressure, your blood pressure is likely to return to normal a few days after delivery. In rare cases, it can take 6 weeks or more. Some women still have high blood pressure 6 weeks after childbirth yet return to normal levels over the long term.

If your blood pressure is still high after delivery, you may be given a blood pressure medicine. You will then have regular checkups with your doctor.

After having pre-eclampsia, you have a higher-than-average risk of heart disease, stroke, and kidney disease. This may be because the same things that cause pre-eclampsia also cause heart and kidney disease. To protect your health, work with your doctor on living a heart-healthy lifestyle and getting the checkups you need.


Lowering your blood pressure helps to prevent pre-eclampsia. If you have chronic high blood pressure, you can lower your blood pressure before pregnancy by:

  • Exercising.
  • Eating a diet low in sodium and rich in fruits and vegetables.
  • Staying at a healthy weight.

When you are pregnant, regular checkups are key to early detection and treatment. Prompt treatment is vital to preventing the development of severe and possibly life-threatening pre-eclampsia.

To reduce your risk for pre-eclampsia, your doctor may recommend that you take low-dose aspirin during the second and third trimesters of your pregnancy.

Home Treatment

Expectant management

If you develop signs of pre-eclampsia early in pregnancy, your doctor or midwife may prescribe something called expectant management at home, possibly for many weeks.

This may mean you are advised to stop working, reduce your activity level, or possibly spend a lot of time resting (partial bedrest). Although partial bed rest is considered reasonable treatment for pre-eclampsia, experts don't know how well it works to treat mild pre-eclampsia or high blood pressure. footnote 2 It is known that strict bedrest may increase your risk of getting a blood clot in the legs or lungs.

Whether you are required to reduce your activity or have partial bedrest, expectant management limits your ability to work, remain active, take care of children, and fulfill other responsibilities. It may be helpful to follow some tips for dealing with bedrest.

Daily monitoring

You may be required to monitor your own condition on a daily basis. If so, you or another person (such as a trained family member or a visiting nurse) will:

Keep a written record of your results, including the dates and times you checked. Take this record with you when you visit your doctor or midwife.

Social support

Worry and reduced activity are difficult parts of having pre-eclampsia. It often helps to talk with women who are or have been in the same situation.


Medicine for pre-eclampsia may be used to:

  • Control high blood pressure. Lowering high blood pressure doesn't prevent pre-eclampsia from getting worse. That's because high blood pressure is only a symptom of the condition, not a cause. Your doctor may recommend blood pressure medicine if your blood pressure reaches high levels.
  • Prevent seizures. Magnesium sulfate is usually started before delivery and continued for 24 hours after delivery for women with pregnancy-related seizures ( eclampsia ) and those who have moderate to severe pre-eclampsia.
  • Speed up fetal lung development. When possible, steroid medicine is given to the mother prior to a premature birth (up to 34 weeks of gestation). This medicine matures the baby's lungs over a 24-hour period, which lowers the risk of breathing problems after birth.

Blood pressure medicines

Medicines used to control chronic high blood pressure during pregnancy include:

  • Methyldopa.
  • Nifedipine.

Some high blood pressure medicines are dangerous during pregnancy. footnote 3 If you take high blood pressure medicines, talk to your doctor about the safety of your medicine. Discuss this before you become pregnant or as soon as you learn you are pregnant. Make sure that your doctor has a complete list of all medicines that you take.

Other blood pressure medicines that may be used include:

  • Hydralazine. This is an intravenous medicine for quickly lowering severely high blood pressure during pregnancy.
  • Labetalol. It's an intravenous medicine for quickly lowering severely high blood pressure in the hospital. It's also an oral medicine for controlling high blood pressure during pregnancy.

Lowering blood pressure too much or too fast can reduce blood flow to the placenta, causing problems for the baby. So medicine is reserved for preventing severely high blood pressure levels that may be life-threatening to you or your baby.


There is no surgical treatment for pre-eclampsia.

A caesarean section delivery is used when:

  • A rapid delivery is medically needed for the mother's or baby's well-being or survival.
  • Induction of labour has not been successful, usually after 24 hours.
  • There are medical reasons, such as placenta previa , that make vaginal delivery dangerous.

Other Places To Get Help


Society of Obstetricians and Gynaecologists of Canada (SOGC)
Hypertension Canada: Understanding Hypertension



  1. Roberts JM, Funai EF (2009). Pregnancy-related hypertension. In RK Creasy, R Resnik, eds., Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice, 6th ed., pp. 651–688. Philadelphia: Saunders.
  2. Sibai BM (2003). Diagnosis and management of gestational hypertension and preeclampsia. Obstetrics and Gynecology, 102(1): 191–192.
  3. Cooper WO, et al. (2006). Major congenital malformations after first-trimester exposure to ACE inhibitors. New England Journal of Medicine, 354(23): 2443–2451.

Other Works Consulted

  • American College of Obstetricians and Gynecologists (2002, reaffirmed 2010). Diagnosis and management of preeclampsia and eclampsia. ACOG Practice Bulletin No. 33. Obstetrics and Gynecology, 99(1): 159–167.
  • Campbell NRC, et al. (2014). Cardiovascular disorders: Hypertension. In J Gray, ed., Therapeutic Choices. Ottawa: Canadian Pharmacists Association. Accessed June 26, 2014.
  • Magee LA, et al. (2014). Diagnosis, evaluation, and management of the hypertensive disorders of pregnancy: Executive summary. SOGC Clinical Practice Guideline No. 307. Journal of Obstetrics and Gynaecology Canada, 36(5): 416–438. Accessed June 26, 2014.
  • U.S. Preventive Services Task Force (2014). Low-dose aspirin use for the prevention of morbidity and mortality from preeclampsia: U.S. Preventive Services Task Force recommendation statement. U.S. Preventive Services Task Force. Accessed September 16, 2014.


ByHealthwise Staff

Primary Medical Reviewer Sarah Marshall, MD - Family Medicine

Specialist Medical Reviewer William Gilbert, MD - Maternal and Fetal Medicine

Current as ofJune 30, 2014