Pre-eclampsia

Pre-eclampsia is a condition that occurs only during pregnancy, or immediately after the delivery of a baby. Women develop high blood pressure, together with protein in their urine (leaked from their kidneys) and fluid retention (oedema). Although pre-eclampsia is usually mild, it should always be taken seriously because, in a few cases, it can cause complications, such as growth problems in the baby.

Mild pre-eclampsia affects around 1 in 14 women, and usually occurs after the 20th week of pregnancy. It does not always need treatment, and regular check ups on the mothers and baby's health may be all that is required. Some cases can be managed with drugs to lower blood pressure, but this does not prevent pre-eclampsia, it simply controls the condition. The only way to prevent the condition is to deliver the baby, but this depends on the stage of pregnancy because being born prematurely can be dangerous. Babies may also be 'small-for-dates' because of growth problems.

Around 1 in 100 women with pre-eclampsia go on to develop a serious complication called eclampsia. This can happen at any stage during pregnancy, but it is more common during the last three months, and the first 48 hours after birth. Eclampsia is a type of seizure that can be life-threatening. Every year, in the UK, pre-eclampsia is responsible for the deaths of between 7-10 mothers, and up to as many as 1,000 babies.

There are no symptoms in the early stages of pre-eclampsia, and it can only be detected by regular antenatal check ups. It is natural for many women to experience increased blood pressure during their pregnancy, but this alone is not a sure sign of pre-eclampsia. Regular antenatal check ups can determine whether your increased blood pressure is as a result of pre-eclampsia, usually by either your GP or midwife checking for protein in your urine.

Circulation problems develop in pre-eclampsia, which show up as high blood pressure, protein in your urine, and fluid retention. As the condition progresses, your may experience one or more of the following symptoms:

• severe headaches,
• vision problems, such as blurring, or seeing flashing lights before your eyes,
• pain in your upper abdomen,
• vomiting, or
• sudden swelling of your feet, ankles, face and hands, and excessive weight gain because of fluid retention.

You should seek immediate medical advice should these symptoms develop. Without immediate treatment, your condition may deteriorate quickly or you may develop complications.

Complications of pre-eclampsia include:

• eclampsia, a rare, but serious complication that usually occurs late in pregnancies, or just after the delivery of a baby it can include one or more convulsions, or seizure which may lead to coma,
• HELLP Syndrome, a combined liver and blood clotting disorder, occurs in approximately one in five women this involves the pregnant women having (H) haemolytic anaemia (the blood cells begin to break down), (EL) elevated liver enzymes, and (LP) a low platelet count, and
• kidney or lung problems may also develop.

The main sign of pre-eclampsia is the slower growth of your unborn baby, compared to that of a baby that is developing normally. This is due to a poor blood supply through the placenta to the baby, leading to a reduced amount of oxygen and nutrients during their development (called intra-uterine growth restriction).

The cause of pre-eclampsia is not fully understood. However, it is thought that a problem develops with the blood vessels in the placenta causing it to be underdeveloped.

Researchers have discovered that levels of the hormone (activin A) are raised in the blood stream of women with pre-eclampsia, but the reason for this is unknown.

The following factors may mean you are more susceptible to pre-eclampsia:

• if it is your first pregnancy 1 in 30 women tend to develop pre-eclampsia in their first pregnancy,
• if you are a mother who has had a long interval between pregnancies, usually more than 10 years apart,
• if you have a family history of the condition, suggesting a genetic link,
• if you have had pre-eclampsia in a previous pregnancy roughly 20% of women with pre-eclampsia will develop the condition again in later pregnancies,
• if you are a teenager or woman aged over 40 years,
• if you have existing medical problems for example, diabetes, kidney disease, migraines, or high blood pressure,
• if you are obese, or
• if you are expecting multiple babies, such as twins or triplets.

Pre-eclampsia is normally diagnosed when two of the characteristic symptoms of the condition occur together, for instance, if your blood pressure becomes high and you begin to get pains in your abdomen. Approximately one in five pregnant women with high blood pressure progress onto having pre-eclampsia. Both mother and unborn baby will then need to be monitored closely, usually in hospital.

If you begin to display symptoms of pre-eclampsia contact your GP or call NHS Direct on 0845 4647 for advice.

If you are admitted to hospital it is likely the following tests will be carried out:

• blood pressure checks every 4-6 hours to monitor any abnormal increases,
• urine samples taken every 24 hours to measure your protein levels,
• ultrasound scan to check the blood flow through your placenta (intra-uterine growth restriction), and to observe your baby's breathing, and
• foetal heart rate monitor using a cardiotocograph (CTG) monitor may be used to keep a close eye on your baby's immediate wellbeing as it is able to detect distress.

Attempts will be made to manage your pre-eclampsia until a delivery after 36 weeks of pregnancy can be achieved. Treatment is often aimed at lowering your blood pressure, which includes bed rest and medication (such as calcium channel blockers), usually in hospital where your condition can be monitored constantly. You may also be prescribed anticonvulsant drugs as these help to prevent convulsions that are caused by the eclampsia.

The only cure for pre-eclampsia is to deliver your baby and the placenta as soon as possible, usually by Caesarean section (delivery of your baby through an incision in your abdomen). Pre-eclampsia is therefore the cause of around 15% of premature births.

Recent research by the Medical Research Council (MRC) has shown that giving magnesium sulphate injections to pregnant women with pre-eclampsia halves their risk of developing eclampsia. 

New research suggests that the antioxidants contained in vitamin C, vitamin E, selenium, and lycopene can reduce the chance of pregnant women developing pre-eclampsia. Research into treatments of pre-eclampsia is ongoing.

For most women, delivery reverses all the effects of pre-eclampsia and they have normal subsequent pregnancies. However, about 20% of women will have pre-eclampsia in future pregnancies. There is also a slight risk that a few women will have some organ damage due to complications of the condition.