Pre-eclampsia involves high blood pressure and protein in the urine. It can have no symptoms but some women may have headache, blurred vision, tummy pain and swollen ankles. The severity of pre-eclampsia is usually (but not always) related to your blood pressure level. It can be a serious condition but specialist care will help mother and baby stay safe.
What is pre-eclampsia?
Pre-eclampsia is a condition where you have high blood pressure (hypertension) and lose too much protein from your kidneys into your urine. Pre-eclampsia usually comes on some time after the 20th week of your pregnancy and is usually gone within six weeks of you giving birth.
Pre-eclampsia can cause complications for the mother and baby. The more severe the condition becomes, the greater the risk that complications will develop. The only way to cure pre-eclampsia is by giving birth to (delivering) your baby, but the condition can sometimes be stabilised to allow your pregnancy to progress further. Medication may help prevent complications of pre-eclampsia.
Pre-eclampsia is NOT the same as high blood pressure in pregnancy. Many pregnant women develop mild high blood pressure (hypertension), without protein in their urine. This is known as gestational high blood pressure, or pregnancy-induced high blood pressure. There is a separate leaflet called High Blood Pressure in Pregnancy.
What are the symptoms of pre-eclampsia?
You may have no symptoms to begin with, particularly if you only have mildly raised blood pressure and a small amount of protein in your urine.
If pre-eclampsia becomes worse, one or more of the following symptoms may develop. See a doctor or midwife urgently if any of these occur:
- Severe headaches that do not settle with simple painkillers.
- Problems with your vision, such as blurring or flashing lights.
- Heartburn that doesn't go away with antacids.
- Tummy (abdominal) pain. The pain that occurs with pre-eclampsia tends to be mainly in the upper part of your abdomen, just below your ribs, and just to the right.
- Being sick (vomiting) later in pregnancy (not the morning sickness of early pregnancy).
- Rapidly increasing swelling (puffiness) of your hands, face or feet.
- Not being able to feel your baby move as much.
- Feeling unwell.
Note: swelling or puffiness (oedema) of your feet, face, or hands is common in normal pregnancy. Most women with this symptom do not have pre-eclampsia but it tends to become worse in pre-eclampsia. You should report any sudden worsening of swelling of the hands, face or feet promptly to your doctor or midwife.
Rarely, pre-eclampsia and eclampsia can both develop for the first time up to four weeks after you have given birth. This means that should look out for any of the symptoms above after you give birth and report them to your doctor or midwife.
What is HELLP syndrome?
HELLP syndrome is a complication which occurs in women who have severe pre-eclampsia or eclampsia. It commonly occurs between 27 and 37 weeks of pregnancy but can occur any time from 20 weeks. One in three cases occur just after the baby is born. In addition to high blood pressure (hypertension) and protein leakage, HELLP syndrome causes problems with the liver, blood cells and blood clotting.
HELLP stands for 'Haemolysis, Elevated Liver enzymes and Low Platelets', which are some of the medical features of this condition. 'Haemolysis' means that your blood cells start to break down. 'Elevated liver enzymes' means that your liver is affected. 'Low platelets' means that the number of platelets in your blood is low and you are at risk of serious bleeding problems.
It is not certain whether HELLP syndrome is a severe form of pre-eclampsia, or whether it is a different but overlapping disease. HELLP syndrome can occur after pre-eclampsia has been diagnosed, or it may be the first warning of pre-eclampsia. Like pre-eclampsia, it can lead to eclampsia.
What are the symptoms of HELLP syndrome?
HELLP syndrome tends to come on quickly but there may be no symptoms. It can cause similar symptoms to pre-eclampsia. Headaches are common, and some women experience visual symptoms. Other symptoms include feeling unwell, tiredness, pain at the top of the tummy or over the liver area, feeling sick (nausea), being sick (vomiting), and feeling fluey. Symptoms tend to be worse at night. You may have easy bruising or purple spots on the skin, and your liver may become swollen and tender.
You are more likely to develop HELLP syndrome if you are aged over 35 years, having your first baby, have a multiple pregnancy, have had HELLP syndrome before, or have antiphospholipid syndrome. It is more common in white women. Usually the condition resolves fairly soon after your baby is delivered but in about one in three women with HELLP syndrome the condition begins straight after delivery.
HELLP syndrome is an emergency. Doctors need to lower your blood pressure and start you on medicine to reduce your risk of developing eclampsia. Transfusions and plasma exchange can be needed.
The problems caused by HELLP syndrome include clotting problems (1 in 2-20), eclampsia (1 in 20), placental abruption (1 in 5-10 cases) and slow growth in the baby (2 out of 3 cases). In extreme but rare cases, liver failure can occur and transplant is needed. HELLP syndrome can (very rarely) be fatal for mother and baby.
What is eclampsia?
Eclampsia is a type of fit (a seizure or convulsion) which is a life-threatening complication of pregnancy. Fewer than 1 in 100 women with pre-eclampsia develop eclampsia. Almost half of eclampsia seizures occur after delivery, and about 1 in 5 occur during delivery.
How common are pre-eclampsia, eclampsia and HELLP syndrome?
- Worldwide pre-eclampsia affects around 1 in every 20 pregnancies.
- Severe pre-eclampsia occurs in 1 in 200 pregnancies.
- HELLP syndrome also occurs in 1 in 200 pregnancies (but in 1-2 out of every 10 women with severe pre-eclampsia).
- In the UK eclampsia affects only around 1 in every 2,000 pregnancies, although in developing countries the figure is 10 times higher.
- Deaths (of mothers) from eclampsia and pre-eclampsia are very rare - in 2012-2014 there were only three maternal deaths from these conditions in the UK and Ireland.
What causes pre-eclampsia, eclampsia and HELLP syndrome?
These conditions seem to begin when the mother's blood vessels (particularly in the kidney) become leaky and possibly inflamed, in response to a trigger which we believe comes from the afterbirth (placenta).
The placenta connects a mother to her unborn baby, and the baby receives oxygen and nutrients through it. It's thought that the development of the blood vessels of the placenta is different in women who develop pre-eclampsia, and that in these women the placenta may not attach as effectively to the wall of the womb (uterus). This is assumed to trigger the release of substances that then affect the mother's blood vessels.
There is a genetic component to pre-eclampsia, HELLP syndrome and eclampsia - this might be to do with the genetics of mother or of the baby (and the placenta). You are more likely to develop pre-eclampsia if your mother and sisters had it, but also more likely to develop it if the baby's father's mother had it when pregnant with him. These conditions are also more common if you are having twins or more, and in a condition called hydatidiform mole, when abnormal placental tissue forms in the womb.
Who is at risk of pre-eclampsia, eclampsia and HELLP syndrome?
Any pregnant woman can develop these conditions. You have an increased risk, compared to the average risk, if:
Moderate risk factors
- This is your first pregnancy, or it has been over 10 years since your last pregnancy.
- You are aged 40 years or more.
- You are obese (your BMI is 35 or over).
- You are expecting twins, triplets, or more.
- Your mother or sister had pre-eclampsia.
High risk factors
- You have had high blood pressure (hypertension) or pre-eclampsia in a previous pregnancy.
- You have diabetes or chronic (persistent) kidney disease.
- You had high blood pressure before the pregnancy started.
- You have antiphospholipid syndrome. (Women with this condition also have an increased risk of having a miscarriage and of developing blood clots.)
- You have systemic lupus erythematosus. (This condition can cause various symptoms, particularly joint pains, skin rashes and tiredness. Problems with kidneys and other organs can occur in severe cases.)
How are pre-eclampsia, eclampsia and HELLP syndrome diagnosed?
This is diagnosed if:
- Your blood pressure becomes high; and
- You have an abnormal amount of protein in your urine, initially detected with a dipstick in the surgery but usually confirmed on collecting a larger sample, sometimes over 24 hours.
Dr Krishna Vakharia, 30th July 2022
New blood tests known as placental growth factor (PLGF)-based tests have now been recommended by the National Institute for Health and Care Excellence to help decide on care (helps rule in or rule out pre-eclampsia) for people with suspected preterm pre-eclampsia (between 20 and 36 weeks and 6 days of pregnancy).
There are four tests available that can be used at varying points in the pregnancy and your doctor will know which one to use. They can only be used for assessment once in the pregnancy when people have an episode of symptoms of preterm pre-eclampsia.
These tests are recommended to help plan safe care and a safe birth for people with pre-eclampsia. They also identify people who are unlikely to develop pre-eclampsia, and can therefore reduce unnecessary hospitalisation.
There is not enough evidence for use in people who are pregnant with more than one baby. Therefore, these tests cannot be used in people with twins or more.
You can read more about this in the Further Reading section.
This is diagnosed if:
- You have symptoms and signs of pre-eclampsia, particularly feeling unwell with tummy pain, feeling sick (nausea) and being sick (vomiting), or headache; and
- You have abnormalities on blood tests, suggesting the blood and liver changes of HELLP syndrome.
This is diagnosed if:
- You have symptoms and signs of pre-eclampsia or HELLP syndrome; and
- You develop fits or convulsions.
What are the possible complications of pre-eclampsia and HELLP syndrome?
Most women with pre-eclampsia or HELLP syndrome do not develop serious complications. The risk of complications increases the more severe the pre-eclampsia becomes. The risk of complications is reduced if pre-eclampsia is diagnosed early and treated.
For the mother
Serious complications are uncommon but include the following:
- Liver, kidney and lung problems.
- A blood clotting disorder.
- Bleeding into the brain (a stroke).
- Severe bleeding from the afterbirth (placenta).
For the baby
The poor blood supply in the placenta can reduce the amount of food and oxygen reaching the growing baby. On average, babies of mothers with pre-eclampsia tend to be smaller. There is an increased risk of premature birth and of stillbirth. Babies of mothers with pre-eclampsia are also more likely to develop breathing problems after they are born.
What are the possible complications of eclampsia?
The complications of eclampsia are severe for mother and baby. They include an increased level of the risks of pre-eclampsia, and a risk of a type of placental bleed called placental abruption - when the placenta starts to shear off the wall of the uterus (womb).
What is the treatment for pre-eclampsia, HELLP syndrome and eclampsia?
If you develop pre-eclampsia you will usually be referred urgently to see a specialist (an obstetrician) for assessment and care. You may be admitted to hospital.
Tests will be done to check on your well-being and that of your baby; for example, blood tests to check how your liver and kidneys are working and whether your blood is clotting normally, and urine tests to see how much protein is escaping from your kidneys (normally kidneys don't let protein out into the urine). A recording of your baby's heart rate will be done, as well as an ultrasound scan to see how well your baby is growing and a Doppler scan to see how well the blood is circulating to your baby.
Your blood pressure will be checked regularly and your urine will usually be tested at frequent intervals for protein. You should also look out for any symptoms of pre-eclampsia and tell your midwife or doctor if you develop any of these.
If you are less than 34 weeks pregnant with mild pre-eclampsia and you are stable and do not have HELLP syndrome or eclampsia then you may be kept in hospital to stabilise your symptoms, particularly your blood pressure, and be given corticosteroids to try to mature your baby's lung development in case you need an early delivery. If your blood pressure and the other features of the conditions can be stabilised or reduced then you can be kept under observation until your baby is due. If your condition worsens, your baby will most likely be delivered (this may need to be by caesarean section).
Severe pre-eclampsia and HELLP syndrome
More severe cases of pre-eclampsia and HELLP syndrome need intense treatment.
If you are more than 34 weeks pregnant then delivery of your baby (as soon as you are stable) is almost always advised. If you are less than 34 weeks pregnant, and doctors feel that your condition means it is safe enough to delay, you will be given a dose of steroids to help mature your baby's lungs. You will be put on medicines to control your blood pressure and reduce the risk of developing fits (eclampsia). You and the baby will be closely monitored throughout.
If your blood pressure and the other features of the conditions can be stabilised or reduced then you can be kept under observation, often for two weeks or more, until the crucial 34 weeks is reached. If your condition worsens, your baby will most likely be delivered (usually by caesarean section).
Eclampsia (ie you have had a fit) is treated with intravenous medicines to lower your blood pressure and stop you having further fits, and oxygen. Your baby is likely to be delivered as soon as you are stable (see below) and this will usually be by caesarean section. You will be closely monitored for several days afterwards. You are likely to be left on blood pressure medication for some time.
Delivering your baby
The only complete cure for pre-eclampsia, HELLP syndrome and eclampsia is to give birth to your baby. There may be an option of delaying delivery of your baby, usually when less severe pre-eclampsia occurs earlier in your pregnancy. You and your baby will be closely monitored if this is the case, in case your condition becomes more severe.
Severe pre-eclampsia, HELLP syndrome and eclampsia are severe conditions which can pose a risk to your life. Depending on the severity of your condition, and whether it can be stabilised, your baby may need to be delivered early. The best time to give birth to your baby has to balance several factors which include:
- The severity of your condition, and the risk of complications occurring for you.
- How severely your baby is affected.
- The chance of your baby doing well if they are born prematurely. In general, the later in your pregnancy your baby is born, the better. However, some babies grow very poorly if the afterbirth (placenta) does not work well in severe pre-eclampsia. They may do much better if they are born, even if they are premature.
As a rule, if pre-eclampsia is severe then delivery sooner rather than later is best, although if you can be given corticosteroids for 48 hours first this may help the baby's lungs to mature. If pre-eclampsia is not too severe then postponing delivery to give the baby a chance to mature further in the womb (uterus) may be possible.
It may be possible to have a vaginal delivery. This is usually done if you are later in your pregnancy (particularly after 37 weeks), you are stable, the neck of your womb (your cervix) is soft enough to induce and the baby is not distressed. You will need to be recommended to have an epidural (because otherwise labour pain might increase your blood pressure).
Many women whose babies are delivered earlier because of pre-eclampsia, especially more severe cases, are delivered by caesarean section. This is partly because, in severe cases, delivery is at 34 weeks or less when labour cannot easily be induced (because the womb isn't 'ready') and partly because in these cases caesarean section tends to be safer for both you and your baby.
Until your baby is delivered, other treatments that may be considered include:
- Medication to reduce your blood pressure. This may be an option for a while if pre-eclampsia is not too severe. If your blood pressure is reduced it may help to allow your pregnancy to progress further before you give birth to your baby.
- Steroid drugs. These may be advised to help your baby's lungs to mature if doctors feel that there is a chance that they will need to deliver your baby and your baby is still premature.
- Magnesium sulfate. Studies have shown that if mothers with pre-eclampsia are given magnesium sulfate, it roughly halves the risk of them developing eclampsia. Magnesium sulfate is an anticonvulsant (it helps to stop you having a seizure) and it seems to prevent eclampsia much better than other types of anticonvulsants. It is usually given by a drip (a slow infusion directly into a vein) around the time of delivery. It can also have a protective effect on your baby's brain, particularly if your baby is very premature.
Can pre-eclampsia be prevented?
The National Institute for Health and Care Excellence (NICE) recommends that women at increased risk of developing pre-eclampsia should take low-dose aspirin.
NICE recommends 75-150 mg aspirin every day from 12 weeks of your pregnancy until the birth of your baby.
What happens after my baby is born?
Pre-eclampsia usually settles down soon after birth. More severe pre-eclampsia can still cause complications during the first few days (including eclampsia and HELLP syndrome) and you will continue to be monitored closely.
You may need to continue taking medication to lower your blood pressure for several weeks and you may need to stay in hospital for several days. You should see your GP 6-8 weeks after birth for a blood pressure and urine check. If you had severe pre-eclampsia or eclampsia, you should also have a 'follow-up' appointment with your obstetrician to discuss your case.
For a few women, high blood pressure and protein in the urine have not completely settled by six weeks. If this is the case, they will be referred to a specialist.
Will my long-term health be affected?
Some research has shown that women who develop these conditions may have a slightly higher chance of developing high blood pressure (hypertension) and have a higher chance of having a heart attack or stroke in the future. However, the overall risk of developing these problems is still low. Therefore, you may wish to look at ways in which you may be able to reduce your risk of these complications by making changes to your lifestyle. These can include avoiding some combined hormonal contraceptive pills in the future, and keeping to a healthy weight, exercising regularly, eating a healthy, balanced diet and not smoking.
If you have had pre-eclampsia, HELLP syndrome or eclampsia during your pregnancy, it is important that your blood pressure be checked several times after you leave hospital after you have given birth. This will usually be done by a midwife who visits you at home. Your blood pressure will also be checked and your urine checked for protein, at your six- to eight-week check, to make sure that things have returned to normal.
What is my risk of developing pre-eclampsia, HELLP syndrome or eclampsia again in a future pregnancy?
If you had pre-eclampsia in your first pregnancy:
- You have somewhere between a 1 in 2 and a 1 in 8 chance of developing gestational hypertension next time you are pregnant.
- You have about a 1 in 6 chance of developing pre-eclampsia next time you are pregnant.
- If you had severe pre-eclampsia, HELLP syndrome or eclampsia that meant that your baby had to be delivered before 34 weeks, you have about a 1 in 4 chance of developing pre-eclampsia next time you are pregnant.
- If you had severe pre-eclampsia, HELLP syndrome or eclampsia that meant that your baby had to be delivered before 28 weeks, you have about a 1 in 2 chance of developing pre-eclampsia next time you are pregnant.
Being obese is a risk factor for pre-eclampsia (see above). If you have had pre-eclampsia in a previous pregnancy and you are planning for another pregnancy but you are overweight or obese, you should try to lose weight before you become pregnant again. This may help to reduce your chance of developing pre-eclampsia in your next pregnancy.
Dr Mary Lowth is an author or the original author of this leaflet.
Further reading and references
Hypertension in pregnancy: diagnosis and management; NICE Guidance (June 2019)
Antenatal care for uncomplicated pregnancies; NICE Clinical Guideline (March 2008 - updated February 2019)
PlGF-based testing to help diagnose suspected pre-eclampsia (Triage PlGF test, Elecsys immunoassay sFlt-1/PlGF ratio, DELFIA Xpress PlGF 1-2-3 test, and BRAHMS sFlt-1 Kryptor/BRAHMS PlGF plus Kryptor PE ratio); NICE Diagnostics guidance, May 2016
Bartsch E, Medcalf KE, Park AL, et al; Clinical risk factors for pre-eclampsia determined in early pregnancy: systematic review and meta-analysis of large cohort studies. BMJ. 2016 Apr 19353:i1753. doi: 10.1136/bmj.i1753.
PLGF-based testing to help diagnose suspected preterm pre-eclampsia; NICE Diagnostics guidance, July 2022