Pre-eclampsia and eclampsia
Could you explain what pre-eclampsia is?
Pre-eclampsia is a complication of pregnancy characterized by high BP, protein in the urine and oedema (swelling). These features do not always present at the same time, which can make the diagnosis difficult. The early stages are often symptom less and detection relies, therefore, on regular antenatal checks of your BP and urine. The majority of women who develop preeclampsia will develop only a mild form and will recover well
with delivery of a healthy baby. However, it is potentially life threatening to you and your baby if it is allowed to develop and progress without detection or appropriate management. Mothers with pre-eclampsia can be stabilized but it is only curable by delivery, which puts some babies at risk of death or disability from prematurity.
We do know that, as with pre-existing high BP, there is an inherited tendency for pre-eclampsia to run in families, which is why midwives and doctors ask you about BP in your relatives, particularly in your mother or sisters. Pre-eclampsia is also more common in first pregnancies, in women over 40, and in women who already have raised BP before they get pregnant. Your risk of pre-eclampsia is usually assessed at this first antenatal visit and the appropriate pattern of antenatal care will be determined at that time. Visits will be increased if complications are identified as your pregnancy progresses.
I’m worried that I may get pre-eclampsia when I get pregnant as I already have high BP. Am I at greater risk than women who don’t already have high BP?
Pre-eclampsia is a condition in pregnancy that usually presents with high BP, protein in the urine and swelling (oedema). Your risk of pre-eclampsia is higher if you already have high BP but we don’t know by exactly how much. Depending on your age, weight and family history, your risk of pre-eclampsia can be anythingfrom 2 to 10 times that of a woman who did not have raised BP at the beginning of her pregnancy.
The problem is that, because most studies have been based on women attending hospital antenatal clinics, they often lack information about BP in women before their pregnancies began. If women are not seen for antenatal care until they are well into their pregnancies at 15–20 weeks (which is still fairly common in women at the highest risk of pre-eclampsia), and if there are no previous medical records about BP, then there is simply no
way of knowing whether a rather high BP is recent and important, or it is long-standing and therefore much less important. A lot of research on this subject has been weakened by this lack of information, so any conclusions have to remain rather uncertain.
The moral of this is that, if any doctor or nurse has at any time been concerned about your BP, you should make sure the details of this are available to whichever professionals become responsible for advising you during your pregnancy. This information will influence your subsequent risk of pre-eclampsia and how your antenatal care is planned.
Because I suffered from pre-eclampsia in my first pregnancy, I have been looking up the subject now that I am pregnant again. I have see the words ‘fulminating pre-eclampsia’, which sounds very daunting. What is fulminating pre-eclampsia?
Fulminating is yet another word that comes from the Latin, and roughly means ‘like lightning’. It can be applied to any illness or condition (not just pre-eclampsia) when it occurs suddenly and with great intensity (in other words, one which strikes like lightning).
Fulminating pre-eclampsia happens very rarely, but when it does, it is an emergency. The term is used to describe the extremely rapid development of pre-eclampsia, over hours or days rather than the more usual weeks. In this rare emergency, BP rises rapidly, large and increasing amounts of protein are passed in urine and fluid is retained so that the face swells upvisibly over a few hours. When this happens the brain can also becomes swollen, and there is then immediate danger of eclamptic fits. Drugs will be used to bring down BP and to prevent fits (usually given by a drip in a vein), and the baby will be delivered as soon as possible either by inducing labour or by caesarean section. Recent research has shown that the best available treatment for women who develop an eclamptic fit is with magnesium (Epsom salts) given into a vein or into a muscle. This hospital treatment decreases the risk of further fits and reduces the danger to both mother and baby.
I presume ‘pre-eclampsia’ just means ‘before eclampsia’, but what exactly is eclampsia?
The word eclampsia comes from the Latin, and literally means ‘flashing lights’. In practice it means fits (seizures) caused by brain damage, caused in turn by very high BP that develops very fast, usually in late pregnancy. Women suffering eclampsia usually see flashing lights just before a fit begins, hence the name. Soon after this, the sufferer suddenly loses consciousness, her whole body shakes symmetrically and uncontrollably, with clenched teeth and severe spasm of all muscles, all for only a minute or two but seeming much longer.
Eclampsia is very dangerous both to the mother and to the unborn child. Before modern antenatal care, deaths from eclampsia in pregnancy were common. They still happen, although very rarely – only in 10 pregnancies in every million. In nearly all cases eclampsia is preceded by pre-eclampsia – either by several weeks of slowly rising BP, or by dramatic warning signs (mainly pain in the upper abdomen caused by congestion of the liver), or by severe persistent headache. The existence of these changes and warning signs means that nearly all cases of eclampsia can be prevented by good antenatal care.
Because pregnancy is now normally well supervised, eclampsia has become very rare and, when it occurs, it may indicate a serious breakdown in health care. Eclampsia is treated by urgent admission to hospital, by giving drugs to control BP and seizures, and by delivering the baby asquickly as possible, after which BP usually falls rapidly to normal without any other treatment.
Does anyone know what causes pre-eclampsia and eclampsia?
Although eclampsia was first identified 150 years ago, its prime cause remains unknown. When we do understand the cause we shall probably find that we should actually be talking about causes in the plural. We already know that there are different patterns to pre-eclampsia, and that these are likely to have different underlying causes.
Pre-eclampsia is somehow related to the placenta. The placenta has its own arteries. In pre-eclampsia these arteries do not penetrate the wall of the uterus (womb) as well as in women without pre-eclampsia, and they seem to be narrowed by plaques of cholesterol and blood clots in much the same way as the coronary and leg arteries are in ‘ordinary’ high BP. This reduces placental blood supply, which somehow induces raised BP throughout the body, with reduced blood flow through the liver and kidneys (untreated, this can lead to kidney failure). The way the blood clots may also be affected and, again, if untreated, blood clotting could be prevented altogether, leading to severe bleeding before, during or immediately after the birth.
All these changes sound frightening but they are rare in modern practice, with regular antenatal supervision and prompt action at the first signs of pre-eclampsia.
I have just learnt that I am pregnant for the first time. How likely is it that I will get pre-eclampsia?
In Western countries about 5% of women expecting their first babies will get pre-eclampsia. In most women it will be in a mild form, but about 1 woman in 250 may get a more severe type of pre-eclampsia.
In some studies as many as a quarter of all women have been found to have some rise in BP during their first pregnancy, instead of the expected fall. However, the accuracy and reliability of BP readings can be affected by many different things, so these rises may be because of anxiety or the number of different people taking the BP measurements.
My mother and my sister both had pre-eclampsia in their first pregnancies. I’ve heard that it runs in families, so what are my chances of having it?
We do know that, as with pre-existing high BP, there is an inherited tendency for pre-eclampsia to run in families, which is why midwives and doctors ask you about BP in your relatives, particularly in your mother or sisters. Estimates vary between a 2-fold and 4-fold increase in your risk of pre-eclampsia with any existing family history. The highest risk is where both a mother and a sister had pre-eclampsia leading to a 10-fold increase in risk. Many of these studies are old, reflecting care when women were having babies in the 1930s and 1940s, and their daughters were having their babies in the 1960s and 1970s. Much has changed in the last 20–30 years, so we would expect the chances of developing pre-eclampsia or eclampsia to be fewer today with our improved antenatal care and earlier inductions when preeclampsia does occur.
It would be sensible for you to tell your obstetrician and the other people caring for you during your pregnancy about this family history of pre-eclampsia. The more they know about your medical history and background, the better they can look after you.
If I do develop pre-eclampsia, will it harm my baby?
The main risks to your baby relate to poor growth and prematurity. Babies born at a lower weight than expected for the stage of pregnancy may take a while to establish a good feeding pattern and steady weight gain. This may mean additional ‘top-up’ feeds as well as breastfeeding and occasionally the baby may need to be fed with a small tube passed into its stomach if he or she has difficulty sucking. Pre-eclampsia may cause premature birth, usually with a birthweight under 2.5 kg (5 lbs 8 oz), or your baby may need to be induced early to protect you, the mother. Either way, depending on the degree of prematurity, this does slightly increase the risk of harm to your baby. Babies who are very immature may need special care in a neonatal intensive care unit. In the very rare cases of severe pre-eclampsia early in pregnancy, there may be a risk of the baby dying or survival with disability.
In my last pregnancy one doctor said I had PIH, another said I had PRH, and the midwife said I had PET. What was going on?
At one time eclampsia and pre-eclampsia were together called toxaemia of pregnancy. There was no attempt to separate several different conditions affecting pregnant women, some of which were caused by problems unrelated to high BP. In recent years doctors have tried to make things clearer (or at least more specific) by trying out different names for high BP in pregnancy. Toxaemia is a term rarely heard today, but pre-eclamptic toxaemia (PET) is still used. Pregnancy-induced hypertension (PIH), pregnancy-related hypertension (PRH), pregnancy-associated hypertension (PAH), hypertension–oedema–proteinurea syndrome (HOP), hypertensive disease of pregnancy (HDP), gestational hypertension and gestosis are names that are all used to describe BP that is raised during the latter part of pregnancy and which gets better after the baby is born. This is all very confusing to the mother! If we must use abbreviations, the most sensible would seem to be PE (for preeclampsia), because eclampsia is real, and is what we are trying to prevent. However, this can be confused with pulmonary embolus (a clot in the lung and also a rare complication in pregnancy). If there is no protein in the urine, then you may well find the abbreviation PIH being used, and many doctors and midwives use PET (pre-eclamptic toxaemia) when there is protein in the urine.
