Pre-eclampsia is a condition that affects some pregnant women, usually during the second half of pregnancy (after 20 weeks) or soon after their baby is delivered. It is a serious condition that needs treatment straight away.

What is pre-eclampsia?

Pre-eclampsia is a condition that affects some pregnant women. It is a combination of raised blood pressure (hypertension) and often protein in your urine (proteinuria) or problems with the kidneys or liver. 

Signs of pre-eclampsia

How common is pre-eclampsia?

Pre-eclampsia can range from mild to severe. Mild pre-eclampsia affects up to 6% of pregnancies. Severe cases are rarer and develop in about 1 to 2% of pregnancies. 

Early onset pre-eclampsia (pre-eclampisa diagnosed before 34 weeks) tends to be more serious than late-onset pre-eclampsia. But early onset pre-eclampsia is much less common. 

What causes pre-eclampsia?

Experts don’t know exactly what causes pre-eclampsia. At Tommy’s, we are funding research to figure out why it happens and how we can stop it.

It may happen when there's a problem with the placenta. The placenta passes oxygen, nutrients and antibodies from your blood supply to your baby. It’s thought that pre-eclampsia develops when the blood supply to the placenta is not as strong.

Is there anything that increases my risk of developing pre-eclampsia?

There are some things that can increase your risk of developing pre-eclampsia. You are at higher risk if:

  • your blood pressure was high before you got pregnant 
  • your blood pressure was high in a previous pregnancy
  • you had diabetes or kidney disease before you get pregnant
  • you have an auto-immune disorder, such as lupus or antiphospholipid syndrome

Other things that can slightly increase your chances of developing pre-eclampsia include if:

  • you are 40 or older
  • this is your first pregnancy
  • your last pregnancy was more than 10 years ago
  • you or a family member has had pre-eclampsia before
  • you have a high BMI
  • you are expecting more than 1 baby

Is there anything I can do to prevent pre-eclampsia?

There’s no guaranteed way to prevent pre-eclampsia. The best thing to do is go to all your antenatal appointments and follow your healthcare professional’s advice.

You may be prescribed low-dose aspirin (75-150 mg) once a day from 12 weeks of pregnancy until you give birth if you have more than 1 risk factor for pre-eclampsia. 

You’ll also be given the same advice as every pregnant woman about exercise and eating well.

There is specific advice for women with pre-existing diabetes or gestational diabetes

Following this advice will help you have as healthy a pregnancy as possible.

What are the symptoms of pre-eclampsia?

The early signs of pre-eclampsia include protein in your wee or high blood pressure. You probably won’t notice this yourself, which is why you’ll have regular urine and blood pressure checks as part of your routine antenatal care.

You may need to have your blood pressure checked more often if you have any signs of pre-eclampsia. 

If the condition gets worse, you may have the following symptoms:

  • a headache that doesn’t go away with simple painkillers
  • vision problems, such as blurring or flashing before your eyes
  • pain just below the ribs
  • feeling sick or vomiting
  • heartburn that doesn’t go away with antacids
  • rapidly increasing swelling of the face, hands or feet
  • feeling very unwell. 

When does pre-eclampsia develop?

Most cases of pre-eclampsia happen after 24 to 26 weeks and usually towards the end of pregnancy.

Although it is less common, the condition can also develop for the first time in the first 6 weeks after your baby is born. 

Can pre-eclampsia lead to other complications?

If pre-eclampsia is severe, it can start to affect other systems of your body. These complications are rare.  But this is why it’s vital to be diagnosed as soon as possible if you have pre-eclampsia. 

Fits (eclampsia)

Eclampsia describes a type of convulsion or fit (involuntary contraction of the muscles). Pregnant women can experience them usually from week 20 of the pregnancy or immediately after the birth.

Most women make a full recovery after having a fit, but they can put you and your baby’s health at risk.

Eclampsia is quite rare in the UK, with an estimated 1 case for every 4,000 pregnancies.   

You will be given anticonvulsant medication to prevent eclamptic fits if:

  • you have or have already had an eclamptic fit 
  • your baby is expected to be born within the next 24 hours
  • you have symptoms such as ongoing or recurring severe headaches, feeling sick or vomiting, severe pain just below the ribs, high blood pressure or vision problems. 

HELLP syndrome

HELLP syndrome is a rare liver and blood clotting disorder that can affect pregnant women. HELLP syndrome happens in about 0.5 to 0.9% of all pregnancies and is more common in women with severe pre-eclampsia. 

It's most likely to develop immediately after the baby is delivered. But sometimes it can appear any time after 20 weeks of pregnancy, and in rare cases before 20 weeks. HELLP syndrome is slightly more common than eclampsia and potentially as dangerous. 

Most women with HELLP syndrome have the key signs of high blood pressure and high levels of protein in their wee. Typical symptoms include:

  • pain just below the ribs
  • feeling sick and vomiting
  • extreme tiredness (fatigue)
  • headache. 

These symptoms can often be worse at night. You can make a full recovery if you get treatment straight away. 

Other complications

These can include:

  • liver and kidney failure
  • stroke (cerebral haemorrhage)
  • fluid in the lungs (pulmonary oedema)
  • blood clotting disorders. 

Your midwife and doctor will be looking for signs of pre-eclampsia throughout your pregnancy, and you’ll get treatment and care immediately if you do develop symptoms. So it is very unlikely that you’ll develop any of these problems.

How can pre-eclampsia affect my baby?

Because the placenta may not be working as well as it should be, the baby may not get all the nutrients and oxygen they need. This may affect their growth. This is called fetal growth restriction

If you are diagnosed with pre-eclampsia, you will usually have extra ultrasound scans to monitor your baby’s growth.

If the pre-eclampsia is severe, the baby may need to be delivered early (before 37 weeks). Premature birth can cause complications, such as breathing difficulties. Premature babies may need to stay in a neonatal intensive care unit, where they can get extra care. In rare cases, babies may be stillborn.  

What is the treatment for pre-eclampsia?

If you are diagnosed with pre-eclampsia, you’ll be referred to a hospital specialist for more tests.
If you have mild or moderate pre-eclampsia, you may be allowed to go home after these tests. Pre-eclampsia can only be cured by delivering the baby. So, you will have extra appointments, possibly every day, until that is possible. 

You’ll probably be advised to have your baby at 37 weeks.

Some women with severe pre-eclampsia may need to stay in hospital for the rest of their pregnancy. This may be on the labour ward or in more serious cases, you may need to be admitted to an intensive care or high dependency unit.

While in hospital you’ll have:

  • regular blood pressure checks
  • regular urine tests (to check your protein levels)
  • blood tests (to check your kidney and liver health)
  • ultrasound scans (to check your baby’s growth and the amount of amniotic fluid surrounding them).

Your baby’s heart rate will also be monitored.  

You may need extra scans to check your baby’s health if you had any of the following in a previous pregnancy:

  • severe pre-eclampsia
  • pre-eclampsia that resulted in a birth before 34 weeks
  • pre-eclampsia with a baby whose birth weight was less than the 10th centile
  • stillbirth
  • placental abruption

Your medical team’s priority will be to stop you from developing complications. You’ll be given medication (tablets) to lower and control your blood pressure. This will help reduce your risk of stroke. 

If your blood pressure can’t be controlled, and your doctor is concerned about your baby’s wellbeing, your baby may need to be born earlier than expected.

Will having pre-eclampsia affect how I give birth?

Yes. If you have mild pre-eclampsia, you’ll probably be advised to have your baby at about 37 weeks. If your healthcare team is concerned about you or your baby, you may need to give birth earlier. If labour doesn’t start naturally, you may need to be induced. If you are having a caesarean section, you may have it earlier than planned.

Babies born before 37 weeks are premature and may need special care. You will probably be given antenatal corticosteroid medication to help improve your baby’s development before they are born.  

If you develop severe pre-eclampsia, the only way to prevent serious complications is for your baby to be born. Exactly when this will be will depend on your situation. You should be given information about the risks of both premature birth and pre-eclampsia so you can make the best decision about your treatment.

You will either be induced or you may need a caesarean section. Find out more about giving birth to a premature baby.

Your baby’s health

Babies born before 37 weeks may have some problems associated with being born prematurely. The earlier in the pregnancy a baby is born, the more vulnerable they are.

Your baby may need to spend some time in the neonatal intensive care unit for extra care. Because pre-eclampsia can affect your baby’s growth, they will probably be small for their gestational age.

What happens after I give birth?

Most cases of pre-eclampsia cause no problems and improve soon after the baby is delivered. But sometimes there may be complications or your symptoms may last a bit longer. You may need to stay in the hospital to be monitored for a while.

You’ll have your blood pressure checked regularly after leaving the hospital. You may also need to keep taking medication to lower your blood pressure for several weeks.

Tell your healthcare team at the hospital, or your GP if you have been discharged, if you get any severe headaches, severe pain just below the ribs or if you have any other symptoms that concern you. 

All pregnant women should have a postnatal appointment 6-8 weeks after their baby is born. Your GP will examine you and decide if you need to keep taking medication. You can also talk to your midwife or health visitor at any time if you have any concerns.

If you are still on medication to treat your blood pressure 6 weeks after the birth, or there is still protein in your wee, you may be referred to a specialist. 

Your long-term health

Having pre-eclampsia increases the risk of developing high blood pressure and heart disease in later life. Taking care of yourself and having a healthy lifestyle can help reduce this risk. Try to:

  • avoid smoking 
  • exercise regularly
  • eat a healthy, balanced diet
  • maintain a healthy weight. 

Will I get pre-eclampsia in my next pregnancy?

If you have pre-eclampsia, you are also more likely to develop it again in a future pregnancy. About 1 in 6 women will develop pre-eclampsia again in a future pregnancy. 

Women who gave birth between 28 and 34 weeks have a 1 in 3 chance of developing pre-eclampsia in a future pregnancy. 

Women who gave birth between 34 and 37 weeks have a 1 in 4 chance of developing pre-eclampsia in a future pregnancy. 

There are things to do before your next pregnancy to make a difference to you and your baby’s health. This includes trying to maintain a healthy weight and being more active if you’re not already. This isn’t always easy, but we have more information that may help. Find out more about planning for pregnancy

More information and support

Action on pre-eclampsia is a UK charity that can provide more information and support to anyone affected by the condition.

NICE (2019). Hypertension in pregnancy: diagnosis and management. National Institute for health and care excellence

NHS Choices. Pre-eclampsia. (Page last reviewed: 07/06/2018 Next review due: 07/06/2021)  

Boyd, Heather et al. (2013) Associations of Personal and Family Preeclampsia History With the Risk of Early-, Intermediate- and Late-Onset Preeclampsia, American Journal of Epidemiology, Volume 178, Issue 11, 1 December 2013, Pages 1611–1619,
NICE (2008). Antenatal care for uncomplicated pregnancies. National Institute for health and care excellence.

NHS England (2020) Saving Babies’ Lives Version 2

Royal College of Obstetricians & Gynaecologists (2012) Pre-eclampsia

Haram K et al (2009) The HELLP syndrome: Clinical issues and management. A Review. BMC Pregnancy Childbirth. 2009; 9: 8. Published online 2009 Feb 26. doi: 10.1186/1471-2393-9-8

Review dates
Reviewed: 28 January 2021
Next review: 28 January 2024

This content is currently being reviewed by our team. Updated information will be coming soon.