Pre-eclampsia: symptoms, risk factors and treatment

Pre-eclampsia is a condition that only occurs in pregnancy or in the weeks after birth. The NHS describes it as a pregnancy-related condition that causes high blood pressure; Tommy's adds that it usually appears after 20 weeks and is marked by high blood pressure and protein in the urine. It is thought to be linked to problems with the placenta, although experts do not know exactly what causes it.

Most of the time it is not severe. NHS inform, the Scottish health information service, says that for some women it can be dangerous for them and their baby, which is the reason for close monitoring by the midwife and obstetrician. Pre-eclampsia can develop at any point in pregnancy, is most likely from 20 weeks onwards, and sometimes begins in the days or weeks after the baby is born.

The earliest signs are high blood pressure and protein in the urine, and the NHS says it is unlikely that you will notice them, which is why they are checked at routine antenatal appointments. As the condition gets worse, other symptoms can appear. The NHS says any of them can be serious and need to be checked immediately.

If you are pregnant, the NHS says to call your maternity unit; if you have recently given birth or cannot reach the unit, call 111.

• A severe headache that does not go away with simple painkillers.

• Vision problems such as blurred vision or seeing flashing lights.

• Pain just below the ribs.

• Sudden swelling of the face, hands or feet.

• Heartburn that does not go away with heartburn medicines, or being sick.

• Feeling very unwell.

The NHS says there is no cure, but treatments help manage symptoms and they usually improve once the baby is born. A specialist, usually in hospital, assesses severity and agrees a care plan with more regular appointments and extra scans. You will usually be given medicine to lower blood pressure and reduce the risk of stroke. Severe pre-eclampsia may need a hospital stay, and medicine to prevent seizures can be given by injection or drip.

It is often safer for the baby to be born early, in some cases before 37 weeks, and labour may be induced or a caesarean offered. Tommy's says that with mild pre-eclampsia you will probably be advised to have the baby at about 37 weeks. After birth, blood pressure checks continue and medicine may be needed for several weeks. Complications described include eclampsia (seizures, rare at around 1 in 4000 UK pregnancies according to Tommy's), HELLP syndrome, stroke and stillbirth. Tommy's adds that pre-eclampsia increases the risk of high blood pressure, heart disease, type 2 diabetes and kidney disease in later life, and that you are more likely to have it again in a future pregnancy.

The NHS lists some factors that make pre-eclampsia more likely. Higher-risk circumstances include diabetes, high blood pressure or kidney disease, an autoimmune condition such as lupus or antiphospholipid syndrome, and having had pre-eclampsia in a previous pregnancy. A further group of factors raises the likelihood somewhat: a first pregnancy, being 40 or over, being from a Black or South Asian ethnic background, a twin or triplet pregnancy, a close relative with pre-eclampsia, a gap of 10 years or more since the last pregnancy and a BMI of 35 or more before pregnancy.

Tommy's presents a similar list. Having risk factors does not mean you will develop it, and many people with pre-eclampsia have none.

Diagnosis relies on the routine checks of pregnancy. Blood pressure is measured and a urine sample is tested for protein at each antenatal appointment. If a midwife or doctor suspects pre-eclampsia, the NHS says you will usually be referred to hospital for further tests, which can include blood tests and ultrasound scans of your baby's growth.

Tommy's describes a blood test for placental growth factor (PlGF); a low level could be a sign of pre-eclampsia, but further tests are needed to be sure. NICE guideline NG133 on hypertension in pregnancy covers diagnosis and management and was updated on when to offer PlGF-based testing in 2023. A baby may also have extra scans to check growth, because the placenta may not be working as well as it should.

The NHS says that if a midwife or doctor thinks you are at higher risk they may prescribe daily aspirin from week 12 of pregnancy until the baby is born, and calcium supplements if you do not get enough from food. It stresses not to start either unless advised by a midwife or GP. Tommy's says there is good evidence that low-dose aspirin slightly reduces the risk of pre-eclampsia and its complications.

Tommy's is clear that there is no guaranteed way to prevent it. Attending every antenatal appointment, following advice and maintaining a healthy weight through a balanced diet and exercise are the main steps.

The NHS says pre-eclampsia symptoms usually go away after your baby is born, but sometimes they can continue after birth. After you leave hospital you may need to take medicine for a few weeks to lower your blood pressure and have regular blood pressure checks. The NHS also says pre-eclampsia can sometimes develop in the days or weeks after birth.

Tommy's says having pre-eclampsia increases the risk of developing high blood pressure, heart disease, type 2 diabetes and kidney disease in later life, and that a healthy lifestyle can help reduce this: avoiding smoking, exercising regularly, eating a healthy balanced diet and maintaining a healthy weight. It suggests talking to your GP about follow-up. In a later pregnancy, Tommy's says about 1 in 5 people who had pre-eclampsia get it again, with the risk varying depending on how early the baby needed to be born.

The NHS says to get urgent medical help if you are pregnant or have given birth in the last few weeks and have symptoms of pre-eclampsia. If you are pregnant, call your maternity unit if you have the number. If you have recently given birth or cannot call your maternity unit, call 111.

The symptoms to act on are a severe headache that does not go away with simple painkillers, vision problems such as blurred vision or flashing lights, pain just below the ribs, sudden swelling of the face, hands or feet, heartburn that does not go away with heartburn medicines, being sick, and feeling very unwell. Tommy's describes eclampsia, a fit, as rare, affecting around 1 in 4000 pregnancies in the UK, so any of these signs needs checking straight away.

On the NHS, blood pressure and urine are checked at every routine antenatal appointment. If a midwife or doctor suspects pre-eclampsia you are usually referred to hospital for further tests and are seen by a specialist, who agrees a care plan with you.

Private maternity care or a private obstetrician can offer extra appointments and scans, but the NHS checks above still matter. Whichever route you choose, make sure your blood pressure and urine results are shared with the team that will deliver your baby, and ask who to call if symptoms start out of hours.