Also Known As
Pregnancy-induced Hypertension
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This article waslast modified on 1 May 2019.

What is pre-eclampsia?

Pre-eclampsia is one of the most serious conditions affecting pregnant women. It is diagnosed when a woman develops high blood pressure (hypertension), protein in her urine (proteinuria), and/or swelling of the hands, feet and/or face during pregnancy. In severe cases, there may be evidence of damage to the kidneys or liver, accumulation of fluid in the lungs, or disturbances of the central nervous system. About 3 to 7 percent of pregnant women develop pre-eclampsia, which can occur after week 20 of pregnancy.

Untreated pre-eclampsia is dangerous because it can harm the mother's organs and lead to seizures. If these seizures, called eclampsia, aren't treated right away, they are usually fatal for a woman and her baby. Pre-eclampsia or eclampsia can also lead to low birth weight in the baby, premature delivery, which can cause health problems in the baby, or placental abruption, in which the placenta comes loose from the uterus before the baby is born, causing bleeding.

Pre-eclampsia can also progress to HELLP syndrome, another life-threatening condition. It is called HELLP because it is defined by the breakdown of red blood cells (Haemolysis), Elevated Liver enzymes and a Low Platelet count.

One out of every 200 women with untreated pre-eclampsia progresses to eclampsia. Most cases of eclampsia occur in the third trimester of pregnancy or within 4 days after delivery. Rarely, it may develop up to 6 weeks after delivery.

Pre-eclampsia sometimes causes symptoms that are very similar to those of normal pregnancy. Some women with pre-eclampsia may have no symptoms at all. That is why it is important to regularly attend all antenatal appointments. During the checkup, the healthcare professional will perform a physical examination and perform laboratory tests to look for the "silent" signs of pre-eclampsia, like high blood pressure and protein in the urine.

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About Pre-eclampsia
  • Risk Factors

    Researchers are still trying to establish the exact cause of pre-eclampsia. However, it is associated with certain risk factors. These include:

    • A past pregnancy with pre-eclampsia
    • A family history of pre-eclampsia
    • Being pregnant for the first time
    • Being older than age 35 at the time of pregnancy
    • Obesity
    • Carrying multiple babies
    • A history of other conditions, including chronic high blood pressure, migraine headaches, type 1 or type 2 diabetes, kidney disease, a hypercoagulable state (increased tendency for blood to clot), antiphospholipid syndrome, or lupus.
  • Signs and Symptoms

    Pre-eclampsia is a serious complication of pregnancy that can develop with no obvious symptoms. If symptoms are present, they may seem similar to those experienced during normal pregnancy. For example, weight gain and swelling are pre-eclampsia symptoms that also occur during normal pregnancies. High blood pressure is a sign of pre-eclampsia that typically goes unnoticed until a healthcare professional detects it during a routine ante-natal visit.

    If you have symptoms associated with pre-eclampsia or notice sudden changes in your pregnancy, it is important that you let your healthcare professional know right away. He or she will look for other signs of pre-eclampsia and help monitor your symptoms. Untreated pre-eclampsia is a serious condition that can be fatal for you and your baby. Ensure you attend all ante-natal checkups and seek medical attention if symptoms arise.

    Symptoms of pre-eclampsia may include:

    • Sudden weight gain of more than 2 pounds in a week
    • Sudden face and hand swelling (oedema)
    • Persistent headaches
    • Vision changes: temporary loss, blurry vision, flashing light sensations, or light sensitivity
    • Bluish skin resulting from poor circulation
    • Nausea or vomiting, especially if it suddenly appears after mid-pregnancy
    • Decreased urine output
    • Shortness of breath caused by fluid in the lungs or increased blood pressure
    • Shoulder pain or stomach pain or pinching, especially in the upper right side of your abdomen or when laying on your right side—may indicate liver problems

    Some signs of pre-eclampsia that may be detected during a physical examination include:

    • Elevated blood pressure
    • Unusually strong leg reflexes (i.e., when a healthcare professional taps your knee with a rubber hammer)

    Blurred vision, severe headaches, abdominal pain, and shortness of breath are all serious symptoms of pre-eclampsia. If you have any of these symptoms you should seek immediate medical care.

  • Complications

    If left untreated, pre-eclampsia can lead to serious and life-threatening complications for a mother and her baby.

    Possible complications include:

    • Seizure (eclampsia)
    • Liver rupture
    • Stroke
    • Low birth weight in the baby
    • Placental abruption (the placenta comes loose from the uterus before the baby is born and causes bleeding)

    Women with a history of pre-eclampsia are more likely to develop:

  • Tests

    There is currently no one reliable test for pre-eclampsia early in pregnancy.

    During routine antenatal appointments, a healthcare professional will look for signs and symptoms of pre-eclampsia, including high blood pressure, hand and face swelling, and unusual weight gain. In the second and third trimesters, urine is tested for high amounts of protein, a possible sign of pre-eclampsia.
    If you have signs or symptoms of pre-eclampsia, your healthcare professional will do additional laboratory and imaging tests to diagnose pre-eclampsia and determine its severity.

    Laboratory Tests

    Protein in the urine (proteinuria) was once considered a diagnostic sign of pre-eclampsia. However, not all women with pre-eclampsia will have proteinuria. Now, a healthcare professional will look for high blood pressure along with proteinuria, or high blood pressure plus one of a number of other signs and symptoms, including a low platelet count, poor kidney function, poor liver function, severe changes in vision, or oedema.

    The following tests will help to diagnose pre-eclampsia, determine its severity, and monitor its progression:

    HELLP syndrome is a life-threatening variant of pre-eclampsia that is defined by Haemolysis (the breakdown of red blood cells) Elevated Liver enzymes, and a Low Platelet count. If your healthcare practitioner suspects you may have HELLP syndrome, the following tests may be done:

    • Blood film – red blood cells are examined with a microscope for damage or abnormalities.
    • Serum lactate dehydrogenase (LD) – elevated LD levels indicate tissue or cell damage, as occurs in the breakdown of red blood cells.
    • Total bilirubin – elevated levels of bilirubin are an indication of liver damage or red blood cell haemolysis.

    Newer tests being introduced into clinical practice and now recommended by NICE (the National Institute for health and Care Excellence) are those based on two proteins abbreviated as PlGF and sFlt. The concentration of these proteins increase in the maternal blood during pregnancy and influence the development of blood vessels in the placenta, a process called angiogenesis, a critically important process for growth. PlGF (placental growth factor) promotes blood vessel formation whereas sFlt (soluble fms-like tyrosine kinase) inhibits this process. During pre-eclampsia there is a disturbed balance of these two proteins which is observed as a reduction in PlGF and an increase in sFlt in the mothers blood. The consequence is restricted blood flow to the baby through the placenta which can have health effects on both mother and baby.

    Testing to detect the pre-eclampsia may use either PlGF alone, which may be lower in pre-eclampsia, or a measurement of both proteins where the increased ratio of sFlt to PlGF can guide the diagnosis towards pre-eclampsia. The current NICE guidance has said that in women, whom doctors think may have pre-eclampsia and who are between 20 weeks and 34 weeks in pregnancy, the PlGF test with other diagnostic tests and follow-up checks can be used in the NHS to help doctors decide that a woman does not have pre-eclampsia. A growing number of UK laboratories are adopting the NICE guidance and providing these tests.

    Non-Laboratory Tests

    • Ultrasonography – used to assess the baby's health, make sure pre-eclampsia isn't restricting the baby's growth, and check for blood flow in the umbilical cord
    • Non-stress test – a non-invasive test used to monitor the baby’s health by checking the heart rate and oxygen supply
  • Prevention and Treatment


    While many risk factors for pre-eclampsia cannot be controlled, there are some things you can do to reduce your risk of high blood pressure:

    • Avoid additional salt in your meals
    • Drink 6 to 8 glasses of water per day
    • Avoid fried and processed foods
    • Exercise regularly

    NICE recommends that pregnant women who have a higher risk of developing pre-eclampsia are offered a prescription of aspirin (unless this is unsuitable) to take every day from 12 weeks of pregnancy until their baby is born.


    Delivering your baby is the only cure for pre-eclampsia. In deciding when to deliver, your healthcare professional will try to minimise your risk from pre-eclampsia while allowing your baby the maximum time to mature.

    If your pregnancy is far enough along (usually at least 37 weeks), your healthcare professional may recommend delivery to reduce the risk of your condition progressing to eclampsia. You may need to undergo a Cesarean section (C-section) or induction of labour.

    If it is too early to deliver your baby, you may be able to manage pre-eclampsia at home. In this case, your healthcare professional will recommend bed rest, staying well hydrated, and eating less salt. Sometimes you may be given medication to reduce your blood pressure.

    If you are hospitalised for pre-eclampsia, you and your baby will be closely monitored. You may be given medicine to lower your blood pressure and prevent seizures. If your pregnancy is less than 34 weeks, you may be given steroid injections to help speed up your baby's lung development since an early delivery is more likely.

    Untreated pre-eclampsia is a dangerous condition for you and your baby. It is important that you regularly attend your antenatal appointments and call your healthcare professional if you have symptoms of pre-eclampsia.