What is pre-eclampsia?
Pre-eclampsia is the most common type of hypertensive (high blood pressure) disorder that can develop in pregnancy. The exact cause of pre-eclampsia isn’t really known; research suggests that genetics may play a role with the genetic make-up of some women making them more vulnerable to getting it. Pre-eclampsia is also thought to happen when the blood vessels in the placenta don’t develop properly, so the placenta doesn’t function as it should do.The condition is a combination of unusually high blood pressure (pregnancy-induced hypertension) and protein in the urine (proteinuria).
It develops in some women during the second half of their pregnancy (i.e. from around 20 weeks). Studies show that pre-eclampsia most typically develops after 24 to 26 weeks gestation – often towards the end of pregnancy. The condition can also develop after the baby’s birth. Pre-eclampsia can develop and become serious very quickly, so it can be easy for women to miss the early signs and symptoms until they become quite unwell.
How common is pre-eclampsia?
Firstly, it is important to say that pre-eclampsia affects some women more seriously than others. The ‘mild’ form of pre-eclampsia affects up to 6% of pregnancies. The ‘severe’ form affects around 1-2% of pregnancies.
Whilst many cases of pre-eclampsia are mild, others can be more severe and if not treated quickly, may lead to serious complications for both mother and baby. In general, the earlier in pregnancy that pre-eclampsia develops, the more severe the condition tends to be. Knowing about the signs and symptoms of pre-eclampsia so that it is picked up early and treated promptly is therefore very important.
Signs and symptoms of pre-eclampsia
The early signs of pre-eclampsia include:
- Unusually high blood pressure
- Too much protein in the urine
However, as the condition becomes more severe, additional symptoms are often experienced. These include:
- Severe headaches that do not get better with painkillers
- A rapid increase in oedema (swelling caused by fluid retention) which affects the face, ankles, feet and hands
- Excessive weight gain caused by fluid retention
- Visual disturbances – blurred vision; flashing lights; spots before the eyes
- Severe heartburn that is not relieved by antacids
- Epigastric pain (felt on the upper right-side of the torso; just under the ribs)
- Nausea and vomiting
- Feeling very unwell.
The effects of pre-eclampsia on the mother
Without quick treatment pre-eclampsia can lead to the development of a number of serious complications – termed ‘eclampsia’. Complications are rare and include the following:
An ‘eclamptic fit’ is the term used to describe a type of convulsion (involuntary contraction of the muscles) that happens when the brain membranes become irritated. It is a very rare condition which affects around one in 4,000 pregnancies.
During an eclamptic fit, the woman’s limbs, neck and jaw make involuntary repetitive and jerky movements for a short period of time – usually less than a minute. In some cases, the woman will lose consciousness and wet herself.
The majority of women make a full recovery from eclampsia; however, where convulsions are severe, there can be a small risk of brain damage or permanent disability. Around one in 50 women with full-blown eclampsia will die from the condition and because the unborn baby is deprived of oxygen during an eclamptic fit, it is estimated that around one in 14 babies may die.
Studies have found that Magnesium Sulphate can reduce the risk of pre-eclampsia by 50% and reduce the risk of the mother dying. Because of these research findings, Magnesium Sulphate is now routinely used in UK maternity services to prevent and treat eclampsia. Read more in the section, Management and Treatment, below.
Magnesium Sulfate is an anticonvulsant drug (i.e. it stops seizures / fits) that is recommended by the World Health Organisation as the most effective, safe and low-cost treatment available for severe pre-eclampsia and eclampsia. A three-year international study called, ‘the Magpie Trials’ looked at the efficacy of Magnesium Sulfate and found that women who were given it had a 58% lower risk of developing eclampsia, and a 45% lower risk of dying from eclampsia.
This is a combined liver and blood clotting disorder. The letters in the name spell out each aspect of the condition:
‘H’ – Haemolysis: this is where the red blood cells in the body’s circulatory system break down
‘EL’ – Elevated liver enzymes (i.e. proteins): a high level of enzymes in the liver is a sign of liver damage
‘LP’ – Low platelet count: platelets are substances in the blood supply that are needed for the blood to clot.
HELLP syndrome is a rare condition that occurs in 0.05 – 0.7% of all pregnancies and in 8 – 24% of women who have severe pre-eclampsia.
The main treatment for HELLP syndrome is to deliver the baby as soon as possible, even if the baby is premature. This may involve inducing the pregnancy, or delivering the baby by caesarean section. If the baby does need to be delivered prematurely, women are likely to be given corticosteroid medicine before the birth, which helps the baby’s lungs develop.
A blood transfusion may be recommended if bleeding problems become severe. Medicines will also be given to treat the hypertension and Magnesium Sulphate may be given as an intravenous infusion (drip) to prevent eclamptic seizures.
A full recovery from HELLP is possible and women can go on to have further pregnancies without developing HELLP again.
Cerebral Vascular Accident (CVA or a stroke)
High blood pressure can negatively affect the blood supply to the brain. If the brain does not receive the oxygen and nutrients it needs from the blood brain cells will begin to die resulting in brain damage, and, in the most severe cases, possibly even death. It is extremely rare.
Complications with organs and their functioning
Where pre-eclampsia is not diagnosed, not closely monitored or is untreated, more serious damage can occur in the body, including:
- Pulmonary oedema – the build-up of fluid in and around the lungs which blocks the absorption of oxygen leading to breathing difficulties.
- Liver failure – the liver plays an important role in digesting the body’s proteins and fats; producing bile and excreting toxins from the body. If the liver’s functions are upset, this can seriously damage health and, in severe cases, even lead to death.
- Kidney failure – the kidneys have a vital role in filtering waste products from the blood and excreting them from the body via the urinary tract. Kidney failure causes toxins and fluids to build-up in the body with serious consequences to health and wellbeing.
Disseminated intravascular coagulation (DIC)
It’s a complicated term used to describe problems with the body’s blood clotting function. DIC can result in either
- Too much bleeding because there aren’t enough proteins in the blood to help it clot effectively
- Or, in blood clots forming throughout the body because the proteins become overactive. These clots can block blood vessels, stopping the normal flow of blood to the body’s organs which can damage them.
The effects of pre-eclampsia on the baby
Pre-eclampsia also affects the health and wellbeing of the unborn baby; particularly where the condition develops early in pregnancy.
The developing baby receives nutrients and oxygen via the placenta which are needed for growth and development. However, pre-eclampsia causes the flow of blood through the placenta to be reduced, which means fewer nutrients and oxygen get to the baby.This means that babies of pre-eclamptic mothers often do not grow as well – the terms often used to explain this are ‘intrauterine growth restriction’ (IUGR) and ‘Small for gestational age’ (SGA). Giving birth to a smaller baby is particularly common where pre-eclampsia develops before the 37th week of pregnancy.
If there are serious concerns for the health and wellbeing of mother and baby, the decision may need to be taken to deliver the baby early. Around 15% of induced premature births are because of pre-eclampsia.
Premature babies can face significant health challenges because they are smaller and under-developed. They may require specialist care, monitoring and treatment within a neonatal intensive care unit (NICU), including support with their breathing and temperature control.
Sadly, despite huge scientific advances in both obstetrics and neonatal care, around 1,000 babies die each year as a result of pre-eclampsia. Most of these babies die because of the serious complications associated with being born prematurely; however, some babies are stillborn (die in the womb).
Why are routine antenatal appointments important?
Many women do not recognise the symptoms of pre-eclampsia because they have no need to monitor their own blood pressure or test their urine. It is also easy for headaches to be blamed on other things such as fatigue, tension or stress at work. In fact, hypertension affects 10-15% of all pregnant women, and they don’t all develop pre-eclampsia.
However, where a woman does develop high blood pressure in pregnancy and is also found to protein in her urine, it can mean she has pre-eclampsia and means she will need closer monitoring.
Your blood pressure recording at the very start of pregnancy – taken during your Booking appointment is a good sign of what is ‘normal’ for you. The midwife will take your blood pressure at all your routine antenatal appointments and look out for a sudden or gradually increasing blood pressure, as a possible sign of pre-eclampsia. This is why attending your routine antenatal appointments, and any additional antenatal appointments that are advised, is very important. When your midwife or doctor sees you regularly throughout pregnancy concerns can be identified much sooner and acted on quickly.
What are the risk factors
The research evidence shows us that no one can predict with certainty who will develop pre-eclampsia. However, during your Booking appointment, your midwife will ask about your medical history, lifestyle and family history in order to identify any risk factors that might increase your likelihood of developing pre-eclampsia. If any risk factors are identified, your midwife or doctor will give you more information about pre-eclampsia and explain the need for closer monitoring during your pregnancy.
Where women present with two or more of the following factors, they are considered to be at moderate risk of developing pre-eclampsia:
- First pregnancy (primigravida) or first pregnancy with a new partner
- Women aged 40 yrs or older
- A family history of pre-eclampsia i.e. the woman’s mother or sister
- Multiple pregnancy – twins, triplets or more
- Pregnancy interval of more than 10 yrs since the last birth
- Body mass index (BMI) of 35 kg/m2 or more at Booking.
Studies show there are a number of factors associated with a much greater likelihood of developing pre-eclampsia. High-risk factors include:
- A history of hypertension before conception or in a previous pregnancy
- Type 1 or 2 Diabetes
- A history of chronic kidney (renal) disease
- Having an autoimmune disease e.g. systemic lupus erythematosis or antiphospholipid syndrome.
NOTE: Research also suggests that donor-egg pregnancies are at high-risk of developing pre-eclampsia.
Taking an accurate measure of your blood pressure
Your midwife or doctor should measure your blood pressure using a manual sphygmomanometer (blood pressure measuring device) rather than an automated machine (‘Dina-map’). Taking a manual measurement of your blood pressure is considered to be more accurate. They should also make sure that the blood pressure cuff is the correct size for your BMI. Should you have a higher BMI, a larger cuff should always be used to get an accurate blood pressure measurement.
Can pre-eclampsia be prevented antenatally?
Unfortunately, there is no guaranteed treatment to prevent pre-eclampsia from developing. However, if you are at moderate or high-risk of developing pre-eclampsia you will be advised by your doctor to take 75 mg of aspirin daily from 12 weeks’ of pregnancy until your baby’s birth. You will also be offered extra antenatal appointments to monitor your baby’s growth. It is important not to miss your antenatal appointments during pregnancy and to take any anti-hypertensive medications that you have been prescribed – even if you are feeling well in yourself.
Management and Treatment
Should you be diagnosed with pre-eclampsia, you will need to be admitted to your local maternity hospital for closer monitoring. This is likely to involve an initial assessment in Triage or the Day Assessment Unit (DAU) followed by admission to the antenatal inpatient ward.
Treatment for pre-eclampsia will depend on its severity and currently relies on the use of anti-hypertensive medications to reduce blood pressure, and, if needed, intravenous Magnesium Sulphate. These treatments do not cure pre-eclampsia but do aim to stop it from developing into full-blown eclampsia and help prevent eclamptic fits.
Because pre-eclampsia usually resolves within 48 hours post birth, the decision to deliver the baby is often the best treatment. The doctors monitoring you will make this decision based on the severity of pre-eclampsia, how many weeks pregnant you are and the healthy you and your baby are. They will be considering the risks to your and your baby’s health from the pre-eclampsia versus the risk to the baby from being born prematurely. Some maternity units look to induce labour from 34 – 37 weeks’ pregnant. Where the baby is too premature to be delivered early, the doctors will monitor and manage the pregnancy very closely so the pregnancy can continue for as long as possible.
The next section explains current approaches to managing and treating the different forms of pre-eclampsia:
The midwives will measure your blood pressure at least every four hours per hour and take blood samples that will be used to check your blood clotting properly, and your kidneys are not being adversely affected by the pre-eclampsia.
If the doctors are happy that there are no complications you should be allowed home to rest and will have your blood pressure monitored by your community midwife or at the antenatal clinic. However, if the doctors feel that you need to be more closely monitored and/or need repeated blood tests, they will advise that you remain in hospital. This can be distressing, particularly if you have people at home who rely on you. However, it is important to remember the doctors do not recommend this without good reason.
Midwives will measure your blood pressure at least every four hours and blood samples will be used to check that your blood clotting properly and your kidneys are not being adversely affected by the pre-eclampsia.The doctors will also prescribe anti-hypertensive medication to lower your blood pressure.
Your baby’s health and wellbeing will be monitored by recording their heart beat at least four times a day. You are also likely to have ultrasound scans, which may include Doppler scans that measure the blood flow through the placenta to your baby. This is a good indication of whether the pre-eclampsia is adversely affecting your baby’s health and growth.
If your blood pressure responds well to the anti-hypertensive medication and there are no concerns about your baby’s health, you may be able to go home and return once labour begins. Your community midwife will continue to monitor your blood pressure.
If you haven’t had your baby by 39 – 40 weeks, you may be offered an induction which means that labour is started ‘artificially’. This is because it is not recommended that you go over your due date, even where you have mild pre-eclampsia.
If you develop the severe form of pre-eclampsia you will need to stay in hospital for much closer monitoring. Your blood pressure will be checked at least every four hours, but it may be possible that it is checked even more regularly than this – as often as every 15 minutes until it has stabilised, then at 30 minute intervals until the doctors are happy that treatment has been effective and your blood pressure is within normal limits.
Blood and urine tests will also be performed daily to closely monitor your blood count, clotting function, liver and kidney function, and the amount of protein present in your urine which help identify any developing complications.
You will be prescribed regular anti-hypertensive medications and may need to be given one-off doses of medication should your blood pressure suddenly increase.
The doctors will also monitor your baby’s health, using ultrasound scans (to check their growth and wellbeing) and electronic fetal heart rate monitoring (EFM) with a cardiotocograph (CTG).
Because pre-eclampsia causes fluid retention; your fluid intake and output may need to be carefully controlled and measured. The doctors may also start a drip containing Magnesium Sulphate if they are concerned that eclampsia may be developing or you are at risk of having an eclamptic fit or recurrence of a fit.
Sometimes, despite every effort, a woman’s blood pressure cannot be controlled and concerns about her health and the health of her unborn baby may necessitate early delivery. This decision is never taken lightly and the doctors will consider all the circumstances, explain the options, and their recommendations. These can include advising induction of labour or delivering your baby by caesarean section.
Giving birth with pre-eclampsia
When you are in labour your baby’s heart beat and pattern will need to be continuously monitored using a cardiotocograph (CTG). You may be advised to have a low-dose epidural or combined spinal-epidural for pain relief during labour as this helps to lower the blood pressure.
If labour is induced, the aim is to achieve a vaginal birth wherever possible. However, if the doctors are:
(a) unable to control your blood pressure;
(b) there is fetal distress, or
(c) your kidney, liver or clotting blood results become very abnormal, then the you are likely to be advised to deliver your baby without delay by caesarean section.
As previously mentioned, pre-eclampsia improves soon after childbirth, although it is likely that you and your baby will need to continue to be monitored closely in the early postnatal period.
If you had moderate or severe pre-eclampsia, it is likely that you will be cared for in a maternity high-dependency unit (HDU) where you will receive one-to-one care from a senior midwife and can be seen regularly by obstetric and anaesthetic doctors. Once your blood pressure has stabilised and the doctors are happy that you are not at risk of eclampsia, you will be transferred to the postnatal ward where you will need to continue taking your anti-hypertensive medications and have your blood pressure monitored regularly. You should expect to stay in hospital for a few days to rest and ensure that your blood pressure remains stable.
In very rare circumstances, where serious complications develop, some women will need to be cared for in an intensive care unit. However, once their condition improves they are transferred back to the maternity unit.
If your baby’s condition allows, they will remain with you whether this is on the Labour Ward, in HDU or on the postnatal ward. However, if your baby is premature or under a certain birth weight (small for gestational age) they will need to be cared for in a neonatal unit. The NICU staff will give you photographs of your baby and keep you updated on your baby’s progress. Once your blood pressure has stabilised and you are well enough to be transferred to the postnatal ward, you will be able to go and visit your baby on the neonatal unit.
It is likely that you will be asked to come back to the hospital for a postnatal clinic review at six to eight weeks’ post birth.
The risk of recurrence
If you had pre-eclampsia in a previous pregnancy, you are at an increased risk (approximately 16%) of developing the condition in a future pregnancy. If you suffered from a severe form of pre-eclampsia, the risk of recurrence can be as high as 50%However, the extent of the risk depends on how many weeks into your pregnancy the pre-eclampsia developed, the severity of the condition, and the presence of any underlying medical illnesses or conditions at the time.
The risk of recurrence can understandably influence whether or not you choose to have another baby. Your midwife and doctor can discuss this with you in more detail and offer you and your partner specialist counselling. They will explain the closer monitoring that is recommended for future pregnancies. It is important to remember that many women who experience pre-eclampsia in their first pregnancy will go on to have straightforward pregnancies.
Reading this article about may have left you feeling concerned, a little scared or anxious. However, it is important to remember that only a relatively small number of women develop pre-eclampsia and an even smaller number of women, go on to develop eclampsia.
At New Life Classes we want to highlight the importance of being vigilant to the signs and symptoms of pre-eclampsia. In its early stages, pre-eclampsia is symptom-less and can only be picked up by regular antenatal appointments for blood pressure monitoring and urine testing. Therefore, it is very important that you do not miss your routine antenatal appointments, and if for any reason you do, that you re-book the appointment at the earliest opportunity.
If you think you might be developing pre-eclampsia you should always contact your midwife or doctor immediately and get checked out. Studies show us that where pre-eclampsia is detected early and treated quickly, the outlook for both mother and baby is much better.