As many as one in twenty pregnancies are affected by pre-eclampsia, which can be very dangerous for mother and baby if left untreated.
Pre-eclampsia is a serious condition that only occurs during pregnancy, typically after 20 weeks . It is a combination of hypertension (raised blood pressure) and proteinuria (the presence of protein in your urine). Sometimes other organs, such as the liver or kidneys can become affected and there can be problems with blood clotting.
Pre-eclampsia literally means 'before eclampsia' as it can potentially progress to a more dangerous condition known as eclampsia, which occurs in one in 2,000 pregnancies. Eclampsia can cause fits or convulsions. In severe cases, eclampsia can sometimes cause the death of the mother or the baby. Therefore, it is important to manage the condition safely.
Pre-eclampsia is thought to affect one in twenty of all pregnancies. In most of these cases, it will be a mild case and may have no effect on pregnancy. Approximately one in two hundred women will go on to develop severe pre-eclampsia.
Signs and symptoms of pre-eclampsia
Women with mild pre-eclampsia may not show any symptoms, and is usually only discovered during routine antenatal appointments (through standard blood pressure checks and urine samples). The main signs are raised blood pressure combined with the presence of protein in the urine.
If pre-eclampsia gets more severe, more serious symptoms can develop, including:
- blurred or altered vision
- severe heartburn
- nausea or vomiting
- shortness of breath
- severe oedema (swelling of the face, hands and/or feet)
Causes of pre-eclampsia
Although pre-eclampsia has been recognised as a disorder for around 150 years, its exact cause remains unknown. Research indicates that the following may be factors.
Women are more likely to suffer from pre-eclampsia if their mothers and sisters have a history of it.
Women who have already had pre-eclampsia in one pregnancy have an greater chance (16 to 25 percent, and 55 percent if their previous baby was delivered before 28 weeks) of developing it again in a next pregnancy.
However, women with a previous pregnancy or pregnancies without pre-eclampsia have less chance of developing it in subsequent pregnancies. Therefore it appears that there is something in the make-up of some women that makes them more vulnerable to the condition than others.
It is believed that the placenta is involved in the development of pre-eclampsia. The placenta connects a mother to her unborn baby and the baby receives oxygen and nutrients through it. It is thought that the development of the blood vessels of the placenta is incomplete in women who develop pre-eclampsia.
Who is at risk of developing pre-eclampsia?
As we do not know the exact causes of pre-eclampsia, it is hard to predict who will develop it during pregnancy and who won’t. However, you are considered at greater risk if:
- this is your first pregnancy / your first pregnancy with a new partner
- you are aged 40 or over
- you, your mother or sister had pre-eclampsia during pregnancy
- you have a BMI (body mass index) of 35 or more/you weigh 90 kg or more
- you are having a multiple pregnancy (twins, triplets or more)
- you have a medical problem such as high blood pressure, kidney problems and/or diabetes
- you are pregnant from egg donation.
Treatment of pre-eclampsia
Most women with pre-eclampsia will need to be admitted to hospital.
If your regular appointments and checks pick up any symptoms of mild pre-eclampsia, you will be closely monitored for the rest of your pregnancy. Most women will be admitted to hospital for monitoring. You will have more frequent blood tests and scans. You may also be given medicine to control your blood pressure.
It is not recommended that you go over your due date, even with mild pre-eclampsia, so if your baby isn’t born by that date, your labour will be induced. Some hospitals may offer induction from 38 weeks’ gestation.
If mild pre-eclampsia progresses to more severe pre-eclampisia you will be monitored in hospital in case you need treatment and/or the baby needs to be delivered. If necessary you will get medication to control your blood pressure. You will be cared for by an experienced midwife, senior obstetrician and anaesthetist.
You may have the following tests
- Regular blood pressure checks: If you are stable and are showing no symptoms, this will most likely be every four hours. However, if the pre-eclampsia is severe, this may be as often as every 15 minutes, and after you have stabilised, every half hour.
- Daily urine tests: If the pre-eclampsia is severe, you may have a catheter in your bladder to measure how much urine your kidneys are producing hourly, and this will need to continue after the birth.
- Blood tests: These will be taken to check your blood count, clotting, liver and kidney function.
- Ultrasound scans: These scans will help your medical team to measure your baby’s growth and wellbeing.
- Fetal heart monitoring: While in labour, your baby’s heart rate will be monitored continuously.
The only way to cure pre-eclampsia completely is to deliver the baby and the placenta. This might need to be done by caesarean section, particularly if the pre-eclampsia is severe and develops early . Pre-eclampsia is therefore the cause of around 15 percent of induced premature births.
Women are usually delivered if the doctors can’t control your blood pressure, if the liver, kidney or clotting blood tests become very abnormal or if the baby becomes distressed.
Most women with severe pre-eclampsia will need to be delivered within two weeks of being diagnosed of it.
If you develop pre-eclampsia in late pregnancy, it is common practice to induce the baby. The risk to your baby is small if he or she is born just a few weeks early.
However, if you are less than 34 weeks, the decision between delivery or other treatment will depend on the severity of the pre-eclampsia (and its risks to you and the baby) versus the risk of being born prematurely to your baby. Every situation is different and your medical team will discuss all the options with you and let you know what the risks are.
What happens after the birth?
It is likely that the baby will be healthy but he or she will still be monitored. You will also be monitored closely and may have medicine to control your blood pressure. Raised blood pressure can last for up to three months after the birth.
You will be monitored in a high dependency unit until the medical team is sure you are stable and not at risk of having eclampsia. You will need to rest and recover in hospital but you are likely to make a full recovery.
Your baby’s health is also likely to be fine once he or she is born, but if he or she was born prematurely there may be complications associated with that, depending on how prematurely they were born.
If you have been told you are at risk of having a premature baby, you may like to read more about prematurity. You can order our comprehensive guide Having a premature baby free of charge from www.tommys.org/book
For more information, download a copy of Tommy's pre-eclampsia leaflet.
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HELLP syndrome is a particularly severe form of pre-eclampsia.
Symptoms include haemolysis (where the red blood cells disintegrate), raised levels of liver enzymes and a low count of platelets (white blood cells).
The main symptoms are:
- nausea and vomiting
- upper abdominal pain
- vision problems.
It can cause severe breathing difficulties for the mother and severe health problems for the baby. HELLP syndrome occurs in 0.05 to 0.7% of all pregnancies and in 8-24% of cases with severe pre-eclampsia.
Also in this section
Royal College of Obstetricians and Gynaecologists (2007) Pre-eclampsia: what you need to know, http://www.rcog.org.uk/womens-health/clinical-guidance/pre-eclampsia-what-you-need-know
Action on Pre-eclampsia (APEC) Your Questions Answered, http://www.apec.org.uk/faq.html
Royal College of Obstetricians and Gynaecologists (2006) The Management of Severe Pre-eclampsia/Eclampsia, http://www.rcog.org.uk/files/rcog-corp/GTG10a230611.pdf
Royal College of Obstetricians and Gynaecologists (2007) Treating and preventing eclampsia - new figures released in 'The British Journal of Obstetricians and Gynaecologists' at http://www.rcog.org.uk/news/treating-and-preventing-eclampsia-new-figures-released
National Institute for Health and Clinical Excellence (2010) Hypertension in pregnancy: The management of hypertensive disorders during pregnancy at http://www.nice.org.uk/nicemedia/live/13098/50418/50418.pdf
EMIS (2010) Pre-eclampsia, Egton Medical Information Systems http://www.patient.co.uk/showdoc/23069028
Lain K, Roberts JM (2002) Contemporary concepts of the pathogenesis and management of preeclampsia in JAMA, 287:3183–6
National Perinatal Epidemiology Unit (2011) HELLP Syndrome, NPEU https://www.npeu.ox.ac.uk/ukoss/current-surveillance/hellp-syndrome#r2
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