Pre-eclampsia

Published by Bupa's health information team, June 2009.
 
This factsheet is for women who have pre-eclampsia, or for people who would like information about it.
 
Pre-eclampsia is a condition that occurs in pregnant women. It causes high blood pressure in the mother and can cause eclampsia (fits) and other serious problems. In the baby it can result in growth problems, premature birth and stillbirth. It affects one in 25 of all pregnancies.
 

About pre-eclampsia
Symptoms of pre-eclampsia
Complications of pre-eclampsia
Causes of pre-eclampsia
Diagnosis of pre-eclampsia
Treatment of pre-eclampsia
Prevention of pre-eclampsia

About pre-eclampsia

 
Pre-eclampsia is a condition that can develop in pregnancy. It increases your blood pressure and can affect your kidneys, liver, brain and the placenta. It can also harm your baby.
 
As well as pre-eclampsia, there are two other main reasons why you might have high blood pressure in pregnancy. Firstly, your blood pressure may have been high when you became pregnant – sometimes long-standing high blood pressure (chronic hypertension) is diagnosed for the first time during the routine check-ups you have when you are pregnant. If you have chronic hypertension you are at increased risk of developing pre-eclampsia.
 
The other type of high blood pressure during pregnancy is known as pregnancy-induced hypertension (PIH). This is when high blood pressure develops after 20 weeks of pregnancy, but you don't have the other signs of pre-eclampsia and your blood pressure returns to normal soon after delivery. Half of women who have PIH before 32 weeks of pregnancy go on to develop pre-eclampsia.
 

Symptoms of pre-eclampsia

 
During normal pregnancy, your blood pressure tends to fall during the first and second trimesters (up until 24 weeks of pregnancy). With pre-eclampsia, high blood pressure develops after around the 20th week of pregnancy, and stays high until the baby is born.

If you develop mild pre-eclampsia, you won’t have any symptoms – and it’s often first found when your blood pressure and urine are checked during a routine antenatal visit.
If your condition is more advanced, you may get the following symptoms:
 

• severe and persistent headache
• vision problems such as flashing lights, blurred vision, stripes, ‘floaters’ or blackouts
• severe pain just below your ribs, especially on the right side
• swelling, of your face, hands or feet that develops suddenly
• vomiting or feeling sick

 
These symptoms aren't always due to pre-eclampsia, but if you have any of them it’s important to talk to your midwife or GP.

Complications of pre-eclampsia

Complications affecting you

 
Pre-eclampsia doesn’t just affect your blood pressure – if it's severe it can lead to stroke, kidney failure and liver problems.
 
It’s known as pre-eclampsia because if left untreated it can result in eclampsia. This is when you have a seizure (fit). Eclampsia can happen at any time during the second half of pregnancy, during labour or after delivery. Almost half of women who develop eclampsia develop it after the baby is born, usually within 24 hours of delivery.
 
Eclampsia only affects around two in 100 women with pre-eclampsia, because pre-eclampsia can be treated once it's been diagnosed.
 

Complications affecting your baby

 
In pre-eclampsia, there are problems with the placenta (the organ that supplies blood and nutrients to your baby), which, together with your high blood pressure can reduce the blood flow to your growing baby. This means that he or she may not receive enough oxygen and nutrients. This can slow your baby's growth, a condition called intra-uterine growth restriction (IUGR). This is sometimes picked up during a routine antenatal appointment, if your midwife or GP finds that your uterus (womb) measures smaller than expected for your stage of pregnancy.
 
If the oxygen supply to your baby continues to be reduced, he or she may need to be delivered early or even immediately. If this happens before you’re 37 weeks’ pregnant, your baby will be premature. Premature babies are at risk of complications because many of their organs (especially the heart and lungs) may not be ready to work outside the womb. The earlier a baby is delivered, the greater the risk of serious medical complications. However, this needs to be balanced against the risks of your baby not receiving enough oxygen if he or she is not delivered early.
 

Causes of pre-eclampsia

 
Doctors don't know the exact cause of pre-eclampsia. However, it seems to start with a problem with the placenta. In pre-eclampsia the placenta has not properly developed and its blood supply is reduced.
 
Doctors don't know why some women get pre-eclampsia and others don’t, but there are certain factors that put you at a higher risk. Your family history is important – if your mother had pre-eclampsia, there is a two in 10 chance that you will develop pre-eclampsia during pregnancy too.
 
You’re also more likely to get pre-eclampsia if:
 

• this is your first baby
• you had pre-eclampsia in an earlier pregnancy
• you have had a long interval (more than 10 years) between pregnancies
• you’re having twins or other multiple pregnancies
• you're over 40
• you have other medical conditions including high blood pressure, diabetes, kidney disease and antiphospholipid syndrome
• you’re obese, ie you have a BMI (body mass index) of over 35

Diagnosis of pre-eclampsia

 
You may be diagnosed with pre-eclampsia if your blood pressure is raised and protein shows up in your urine when you go for your antenatal check-ups, or if you have symptoms of pre-eclampsia. If your doctor thinks you have pre-eclampsia you will usually need to go to hospital for more tests. You may need to stay in hospital until the baby is born.
 
You will probably have the following tests if you have been diagnosed with pre-eclampsia:
 

• blood pressure checks about every four hours, or more frequently depending on how serious your condition is
• urine collection over 24 hours to measure the exact amount of protein in your urine
• blood tests, including kidney, liver and blood clotting tests
• ultrasound scans to check for intra-uterine growth restriction, blood flow in the umbilical cord and the volume of liquid around your baby

Treatment of pre-eclampsia

 
Pre-eclampsia can only be ‘cured’ when your baby is born. However, you might be given blood pressure lowering medicines such as methyldopa or nifedipine, which can help reduce the risk of complications. Before the birth, your doctors and midwives will closely monitor you and your developing baby in hospital, so that they can deliver your baby before any serious problems develop. If your condition is stable, it's better to wait for labour to start normally because an induced labour is more likely to be long or result in an emergency caesarean section.
 
If you develop severe pre-eclampsia or eclampsia you may be given medicine called hydralazine or labetalol to reduce your blood pressure. This will be given through a drip. You may also be given a medicine called magnesium sulphate, which stops and also prevents fits.
 
If your condition is severe, your baby may need to be delivered immediately. This will often be by caesarean section. If the pregnancy is premature, you may be given steroid injections the day before the delivery. This encourages your baby's lungs to develop and reduces the risk of him or her experiencing breathing difficulties.
 

Prevention of pre-eclampsia

 
If you’re not at increased risk of developing pre-eclampsia, you don't need to do anything specific to help prevent it.
 
A daily low dose of aspirin may reduce the risk of pre-eclampsia in women who have had severe pre-eclampsia in a previous pregnancy, which resulted in premature birth. You should only take aspirin if your doctor has advised you to, because it can cause bleeding during pregnancy.
 
Daily calcium supplements of at least 1g may reduce the chance of pre-eclampsia in high-risk women and in those who don't have enough calcium in their diet. You should only take supplements if your doctor has advised you to.