But a minority of women will develop a potentially serious complication of pregnancy known as pre-eclampsia.
Here we explain exactly what pre-eclampsia is, the symptoms, how to spot it and how it can affect your pregnancy.
What is pre-eclampsia?Pre-eclampsia affects 1 in 10 pregnancies overall and as many as one in five first pregnancies. It develops in the second half of pregnancy any time after 20 weeks. Although most cases are mild, one first pregnancy in 100 is so severely affected that there's serious risk to the life of the baby - and even the mother.
It has been described as 'the disease of theories' because no one really knows exactly causes it. Although there are several significant research projects currently underway, the biology behind it remains poorly understood. What is known is that the condition has its origins in the placenta.
The placenta is a truly amazing organ that feeds and sustains your growing baby by bringing him food and oxygen from your blood. In cases of pre-eclampsia something goes wrong with the placenta which interferes with the blood supply between mother and your baby. This results in high blood pressure.
Signals from the damaged placenta also disrupt kidney function. Waste
products which should be flushed out of the body stay in the blood,
while valuable proteins that should remain in your blood leak into the
Is there a test for pre-eclampsia?
Very often the signs of pre-eclampsia are too subtle in the initial stages so it goes undetected until it's too late to do anything about it.
However, because of the huge numbers of fatalities as a cause of pre-eclampsia each year (nearly 76,000 women and 50,000 babies globally) doctors are trying to develop a more efficient way for early testing of the condition.
A study by Austrian scientists, that has been published in the New England Journal of Medicine, has revealed that a simple blood test could determine whether a mother will develop pre-eclampsia, even if there are no tangible symptoms yet. It works by monitoring the levels of protein in a woman's blood to see if they're at risk.
Dr Verlohen, who ran the study, said: 'This allows us to avoid preterm deliveries and delays in starting treatment.'
The main thing, however, is the fact that it is now possible to reliably rule out disease onset for one week; this will considerably reduce anxiety for the mother.'
It's unknown yet when (or whether) this will be available on the NHS.
Why is pre-eclampsia so serious?'Pre-eclampsia kills around 1000 babies and 7 women every year,' explains Ann Marie Barnard, Chief Executive of the charity Action on Pre-eclampsia.
'The problem is that the majority of mums still haven't heard of it and those who have often don't realise how serious it can be. A lot of women who've suffered from pre-eclampsia ask us: "Why didn't I know about this?" Because when it happens and it's bad it's the most terrifying thing.'
‘There are several crises and bad outcomes which women can experience with pre-eclampsia,' explains Professor Catherine Nelson-Piercy, Consultant Obstetric Physician at Guy's and St. Thomas' Hospitals Trust and Queen Charlotte's and Chelsea Hospital in London. ‘These include Eclampsia and HELLP Syndrome. Eclampsia is serious form of pre-eclampsia that causes seizures in the mother, while with HELLP Syndrome is a combined liver and blood clotting disorder.'
Another crisis that can sometimes happen is placental abruption, where the placenta comes away. Women can also develop problems with their kidneys, problems with their liver and problems with water on their lungs (pulmonary oedema).'
Because there is no cure for pre-eclampsia other than delivery, many babies have to be induced prematurely and sadly not all survive.
What are the symptoms of pre-eclampsia
Pre-eclampsia is particularly dangerous because there are often no visible early symptoms. A combination of rising blood pressure and protein in the urine suggests pre-eclampsia and this is what your midwife will be looking for at your routine antenatal check-ups.
'Many women don't understand the importance of their routine antenatal checks,' explains Ann Marie. ‘I think a lot go along thinking, "Oh god, not another antenatal appointment," particularly if they're feeling all hot and bothered and they've got to sit and wait for a long time.' But attending every antenatal appointment is one of the most important things you can do to safeguard the health of you and your growing baby.
You should have your blood pressure taken and provide a urine sample at every antenatal appointment. Never miss and appointment and if you do have to cancel one, reschedule for as soon as possible.
Know the warning signsDuring the more advanced stages of pre-eclampsia women may experience any, or a combination the symptoms listed below. Even if you haven't been identified as having high blood pressure or protein in your urine, these should always be taken seriously. The symptoms include:
• Swelling or oedema - a certain amount of swelling, particularly puffy ankles, is normal during pregnancy. Oedema associated with pre-eclampsia tends to be accompanied by rapid weight gain and to involve the face and hands. It can come on very suddenly.
• Severe headaches - usually at the front of your head.
• Changes in vision, including temporary loss of vision, flashing lights, blurred vision or light sensitivity.
• Stomach ache, usually under your ribs on the right side
• Feeling or being sick
• Needing to go for a wee less often
• Sudden weight gain, typically more than 2 pounds in a week
Never assume it's normal'The nature of pre-eclampsia is that sometimes women don't get high blood pressure and don't get protein in their urine,' explains Ann Marie. ‘The sort of symptoms these women might present with are a persistent headache and liver pain under the ribs on the right hand side. The problem is that these symptoms could also be dismissed as the normal side effects of later pregnancy,' she warns. ‘Most women get a bit of swelling and most women get a bit of indigestion which is why a lot of the things that you can see with pre-eclampsia can be explained away or misconstrued as relatively normal reactions to pregnancy.'
Be assertiveListen to your own body and if you're feeling really unwell with any of the symptoms described above then don't ignore them and don't be fobbed off with the explanation that they're simply the common side effects of a normal pregnancy. They may not be.
‘It can be hard to challenge what the medical professionals are telling you because I think most of us feel a huge respect for them and we think they know best...but sometimes they don't,' says Ann Marie.
'In my experience women usually do know when something is wrong but sometimes they need to be a lot more assertive. I know this is often hard, particularly when you are pregnant and may be feeling a bit vulnerable. But so many times I have women say to me, "I knew that something wasn't right but no one would listen to me". If you're worried that no one is listening to you and you find it hard to make a fuss then take someone with you who can be your advocate and spokesperson.'
Always get checked outThe reason why we believe that deaths from pre eclampsia are preventable,' explains Professor Nelson-Piercy, ‘ is that most of the women who die from pre-eclampsia die as a result of their high blood pressure.' If the pre-eclampsia is diagnosed quickly and the high blood pressure treated quickly and efficiently then you should be able to prevent women from dying from a stroke or from bleeding in the head which is the reason why most women die from pre-eclampsia in this country. It's about controlling the blood pressure.
You can have high blood pressure and feel absolutely fine. It doesn't necessarily cause symptoms. But if you have symptoms you should go and see your midwife and have your blood pressure checked.
‘If women feel different, unwell or just out of sorts, even if their next appointment isn't for several weeks they should still go and see their GP or their day assessment unit. Most hospitals have a turn up system at their day assessment you don't need an appointment. So get it checked out.'
Who is most at risk?At the moment doctors don't know why some women get pre-eclampsia while others don't. However, they have identified some specific groups of women who are known to be at greater risk. ‘Any woman in a high risk group should be prescribed 75mgs of aspirin per day from the 12th week of pregnancy,' explains Professor Nelson-Piercy. ‘This is also true for any woman who has two of the more moderate risk factors such as being overweight and over 40.'
High risk groups include:
- Women who have suffered from pre-eclampsia during an earlier pregnancy
- Women suffering from one of several chronic conditions. These include chronic kidney disease, certain auto-immune diseases such as lupus, chronic hypertension and Type 1 or Type 2 diabetes.
Moderate risk groups include:
- Women who are having a 1st pregnancy
- Women over 40
- Women expecting multiples,
- Mums who've had a gap of more than 10 years between pregnancies,
- Women whose BMI is 35 or more at their first visit.
- Women with a family history - i.e. a sister or a mum who have suffered from pre-eclampsia.
Will I need to go into hospital?
The NICE guidelines recommend that women with pre-eclampsia should be admitted to hospital,' explains Professor Nelson-Piercy. 'And I certainly believe that this should always be the case.' However, some hospitals take the view that women with mild symptoms of pre-eclampsia can continue at home with more frequent monitoring at their day assessment units.
Pre-eclampsia can very quickly become a life threatening emergency. If you are in hospital you can rest safe in the knowledge that you are in the best possible hands. ‘Once you are in hospital you will be monitored very carefully,' explains Professor Nelson-Piercy. ‘If you do develop very severe complications like placental abruption you are in the right place.'
How long will I be in for?A prolonged stay in hospital, especially if you have other young children to look after, can be hard, particularly if you're not even feeling unwell but it is important to heed the advice of your doctors. ‘I tell my patients that from the point at which pre-eclampsia is diagnosed, the likelihood is that they will need to be delivered within two or three week,' explains Professor Nelson-Piercy. ‘However, it is sometimes possible, though unusual, for women to stay in for up to 10 weeks before they need delivery.'
What will happen in hospital?Once pre-eclampsia has been diagnosed what happens to you in hospital will depend on how advanced your pregnancy is. ‘If you are quite late on into your pregnancy you'll be taken into hospital for your baby to be delivered,' explains Professor Nelson-Piercy. ‘If a woman has reached 37 - 38 weeks there's no point waiting beyond that because her baby's matured.' At this stage the safest option for mother and baby is to induce labour.
If your pregnancy is less advanced then the doctors will weigh up the risks to you against the risk to your baby. ‘As doctors we always prioritise the health of the mother,' explains Professor Nelson-Piercy. ‘If the mother is very sick she will be advised to have the pregnancy ended regardless of what gestation she is. But if she's only 33 weeks we would try and prolong the pregnancy a bit longer because it will be much better for the baby.'
How will I be monitored?Once in hospital you and your baby will be very carefully monitored. You may be given hypertensive medicines to help lower your blood pressure and possibly medicines to prevent fits. You will usually be given blood pressure tablets. ‘These don't control the actual disease,' explains Professor Nelson-Piercy, ‘they just control the blood pressure.'
As well as continually monitoring your blood pressure and changes to levels of protein in your urine, blood tests will be taken to look for signs of kidney or liver involvement as a result of the pre-eclampsia. You may also be given drugs to prevent seizures and/or Heparin to prevent blood clotting.
How will my baby be monitored?Restricted blood flow between you and your placenta can result in a reduced supply of oxygen and nutrients to your baby. This may mean that he doesn't continue to grow as well as expected.
Once pre-eclampsia is suspected or known, your baby will be closely monitored so that he can be delivered before any growth problems become serious. Difficult decisions arise when serious problems of this nature develop in babies under 28 to 30 weeks. Doctors then need to weigh up the baby's chance of surviving outside the womb against those if the pregnancy is allowed to continue.
If you are less than 36 weeks, then steroid injections will be given to help mature your baby's lungs' explains Professor Nelson-Piercy. ‘This is done at admission because it's not possible to predict exactly when your baby's going to need to be delivered.' Once in hospital your baby's heart rate will be regularly checked and ultrasound scans used to check on his growth and wellbeing.
How will it affect my birth?At some point concerns about your safety and/or that of your baby may mean that labour needs to be induced. Given your condition and the nature of an induced birth it does mean that you and your baby will require extra monitoring during labour and you may not be able to have the type of labour and delivery you had hoped for. However, most women with pre-eclampsia do have vaginal deliveries. If your baby is being born prematurely then the special baby care team will be on full alert.
What happens after the birth?
For most women delivery reverses all of the effects of pre-eclampsia. However, this improvement is sometimes preceded by a final crisis. ‘Taking away the placenta gets rid of the cause but not all of the effects,' explains Professor Nelson-Piercy. ‘So it is not at all uncommon for women to get a little worse after they deliver before they ultimately get better.'
What postnatal check-ups will you need?Women will very often be on blood pressure tablets when they are sent home,' explains Professor Nelson-Piercy. ‘Unless they've got pre-existing hypertension they won't need to take these beyond 4-6 after giving birth.' You will also need more frequent checks on your blood pressure and will need to go and see your GP for advice on reducing the dosage.
Again, NICE recommends that anyone with pre-eclampsia gets reviewed at 6 weeks to make sure the high blood pressure and the protein in the urine have gone away. They also need to be counselled about their long term risks.'
Are there any long term implications?Having had pre-eclampsia you are more at risk long term of developing high blood pressure and kidney disease in later life. You are also more at risk of a reoccurrence in subsequent pregnancies.
Kerry Thomson, 36, is mum to Angus, 1 and a new bundle of joy. She was 27 weeks pregnant with her second child when she spoke to us about her pre-eclampsia experience.
'I had all these symptoms but everyone kept telling me it was just part of a normal pregnancy'
It was my first pregnancy and I'd been absolutely fine apart from a bit of early morning sickness. Then I got to about 35 weeks and I just started to feel really crap. I was still working and I just felt rotten really. I was really tired, felt nauseous and then I started randomly vomiting every couple of days. I also had a bad chest pain.
I made a point of telling my midwife about these symptoms at my 36 week appointment she said: "Oh, it's totally normal. Often when you come to the end of your pregnancy you have a rush of hormones and you can feel very much like you did in the first trimester". I hadn't been pregnant before so I didn't question it. Why would I?
I continued working up to 37 weeks but it was a real struggle. I remember leaving work one day and trying to get onto the motorway in rush hour. Then suddenly my mouth started to pour with blood. I remember scrabbling around in my bag trying to get something to stem the flow, while trying to get through the traffic and wondering what on earth I was supposed to do. I was on my own at 6.30 at night, miles from home and I didn't know whether I should pull over or what. In the end I managed to stop it with a parking ticket. (I know now that my platelet count was so low that my blood wasn't clotting properly.)
When I finally got home and my husband saw me with blood all down my top he said he thought I should tell the midwife about it. But the next day I mentioned it in the office and one of the guys whose wife had just had a baby said: "But don't women have 50% more blood in their bodies when they're pregnant? Maybe you just had a cut on your gums or something and you bled more." And I thought: "Oh yes that makes sense."
I actually said to my GP. 'I'm worried I've got pre-eclampsia.'
When I went on my maternity leave I was still vomiting randomly and not feeling great. At 38 weeks I spend a weekend feeling a bit headachy. On the Monday I woke up with a cracking headache right across the front of my head. I took some paracetamol and it just wouldn't shift. The next day it was no better. I knew my midwife had a clinic at the GPs on Tuesdays so I rang and asked her to call back.
I took the dog for a walk and while we were out my vision went all weird. I felt like the ground was coming up to meet me and I just knew it wasn't right. I did know about pre-eclampsia because my grandmother had had it when my father was born.
By about 2pm my midwife still hadn't phoned so I rang again only to be told "Oh I'm really sorry we forget she's on holiday." I then tried ringing my other community midwife but she was out on call. By this point my husband was getting really worried and he insisted that I go to the doctors to get my blood pressure and urine tested.
By then it was about 4.30 in the afternoon. While I was sat in the surgery waiting room the community midwife called me back. When I explained my symptoms she said, "See what the GP says but if you had just told me those symptoms over the phone I would be telling you to get yourself straight to hospital. But as you are seeing him, he'll be able to advise you."
'He told me it was a migraine and that I should just go home and rest.'
So I told my GP my symptoms and explained that I had a family history of pre-eclampsia and that I was worried I had it. He tested my urine which was clear and took my blood pressure. It was 127/77 which he said was not remarkable but my booking in blood pressure was 100/60. So I said to him that for me that was up but he just said, "No, that's totally fine. You've just got a migraine. It's really common in late pregnancy. Go home, your time will come."
So I went home. Fortunately my husband isn't as blasé about things. He said, 'No Kerry, I'm really worried about you. I think we should phone the hospital.' Now we live in a rural area and our hospital is about an hour away. I really didn't want to be bothered going all that way just to be told again that I had a migraine and get sent home. Thankfully my husband got quite cross so I phoned the hospital and they said to come in, so I very grumpily and grudgingly agreed. I honestly thought we'd be coming home again. I wasn't even going to take my bag. We even took the dog with us.
'I just wasn't prepared when they said they wanted to induce me straightaway.'
Once we arrived at the hospital they put me on a trace and took my blood pressure, urine and a blood sample. Over the next couple of hours we kept seeing more and more doctors. They took more blood and the doctor level started getting more and more senior as they came in.
At the time I felt as though they were asking me a lot of random questions, mostly about what my bladder was doing. How often was I peeing? What colour was it? I remember saying I need to pee all the time but nothing was really coming out and that it was a kind of luminous yellow. I thought this was because of my pre-natal vitamins and the pressures on my bladder from the growing baby. Then they brought out a patella hammer and started knocking all my knees and elbows and wrists.
The obstetrician then asked me whether I'd been having a tingling sensation in my mouth at all. For about two weeks I had been having this buzzing in my mouth. Almost like pins and needles. I'd thought I was allergic to something. When I told the doctor I caught him glance across at his colleague. It was then that the penny began to really drop that something was very wrong. Apparently when your kidney function starts to go the electrolyte balance in your body starts to change and this causes the buzzing in your mouth.
The doctors left the room and when they returned they told me that I was suffering from pre-eclampsia and HELLP syndrome because I had low platelets and my kidney and liver functions were completely off. I remember them telling me that they needed to induce me straight away. I was so shocked. I asked whether we could take the dog home and come back in the morning. I was totally unprepared and not in the right frame of mind at all.
'I remember just crying and saying to the midwives, 'I'm so frightened. I'm so frightened'
Being induced was not a nice experience. I found it really scary, painful and invasive. I'd wanted a natural drug free birth. What I got was nothing like it. I was flat on my back with a catheter, a blood pressure monitor and a drip. Because it was quite late at night they said it would take at least 24 hours so they sent my husband home. But once they'd got my labour going things progressed really fast. Not having someone you love to support you was really really scary. I remember just crying and saying to the midwives, 'I'm so frightened. I'm so frightened'. Thankfully he did make it back in time to see Angus born, but it was touch and go whether he'd make it.
'It felt like someone had set me on fire from the insides.'
After Angus was born I had this big euphoric high. I wasn't even worried when the doctor came in and said, 'Kerry we're really worried that you might have a seizure'. He explained that they needed to give me a drug called magnesium sulphate through a continuous infusion for 24 hours and that they needed to put a loading dose in first which could make me feel quite sick. This was the understatement of the century. As the doctor went to do it my phone rang and it was my brother.
I don't even think I said goodbye to him. I just threw the phone down and vomited. It felt like someone had set me on fire from the insides. Magnesium sulphate makes your blood vessels dilate and the initial heat it generates in your body is horrendous. Thankfully this only lasted for the first half an hour when the loading dose took effect. Because it's such a powerful drug they have to examine you every hour over 24 hours. They would check my temperature breathing, reflexes, blood pressure. I was still in the delivery room and they left the lights on through the night. I'd just nod off and they'd wake me up again. It was like Chinese water torture. It was pretty grim.
I had to stay in hospital for a whole week. Every day I would ask if I could go home but my blood tests were still off. I also swelled up a couple of days after the birth and was quite jaundiced. Eventually I was allowed to go home but I had to go to my GP surgery three times a week to have my blood pressure taken and my blood tested. I also had to inject myself in my tummy every day for 6 weeks with a blood thinner. I was so bruised by the end of it.
'I felt very angry for a long time afterwards'
I felt very angry for a long time afterwards particularly towards my GP. I really struggled with that for a while, but I don't feel that any more. I'm OK, Angus is OK and everything turned out fine. I have been able to let it go, but for a long time I'd relive it over and over again in my head and I felt a real need to talk about it'
Bizarrely the decision to have another baby wasn't difficult. I'm 36 and we always knew we wanted three children if possible so we just sort of thought. Well let's crack on. It never put me off. It really didn't. What you get out of it is just so amazing.
This time round I'm not relying on anyone else. I know what my symptoms are and if I get any of them again I'm straight to the hospital. I'm not waiting for a midwife appointment and I'm not waiting for someone to phone me back.
Who can help?If you or someone you know is suffering from pre-eclampsia, or you are worried about pre-eclampsia Action on Pre-eclampsia can provide information and support.
If you are pregnant and worried or feel unwell always contact your GP or midwife immediately.