Pre-eclampsia

Pre-eclampsia is a complication of pregnancy in which, from the second half of the term onwards, blood pressure rises and the mother's organs begin to suffer: the kidneys, the liver, the blood and the nervous system. At the same time the placenta receives less blood, and so does the baby. The starting point is twenty weeks: anything appearing earlier is almost always high blood pressure that was already there before the pregnancy. The defining feature of this condition is that a woman feels perfectly well right up to the point where she does not — which is why it is looked for with instruments rather than by asking about symptoms.

What is happening in the body

It all begins long before the first high reading on the monitor, in the earliest weeks of pregnancy, while the placenta is still anchoring itself to the wall of the womb. Normally the uterine vessels it plugs into open right up and turn into soft, wide channels carrying a large flow of blood. If that remodelling only half happens, the vessels stay narrow and stiff, and the placenta spends the whole pregnancy on a meagre blood supply.

A placenta short of blood releases substances into the mother's bloodstream that damage the inner lining of vessels throughout her body. From there the whole mixed picture of the illness makes sense: vessels tighten and pressure rises; the kidney filter starts letting protein through and it turns up in the urine; fluid leaves the vessels for the tissues, so the face and hands swell and, in severe cases, the lungs; the liver suffers and there is pain under the right ribs; platelets are used up and the blood clots less well.

This also leads to an uncomfortable conclusion: as long as the placenta is in the womb, the source of the problem is still there. Medicines bring the pressure down and guard against seizures, but they do not cure pre-eclampsia. It ends only with the birth of the baby and the delivery of the afterbirth.

Why it is found at an appointment rather than felt

The two earliest signs of pre-eclampsia, raised blood pressure and protein in the urine, cannot be felt at all. Neither hurts, neither disturbs sleep, neither affects mood. That is why blood pressure is taken and a urine sample requested at every antenatal appointment: it is not a formality but the only way of catching the condition before it announces itself.

Feeling well guarantees nothing here. Weeks may pass between the first rise in blood pressure and serious complications — or two days may pass, and there is no telling in advance. Most women who go on to have an eclamptic seizure felt entirely ordinary the day before.

The practical point is simple: do not postpone or skip antenatal appointments, especially in the third trimester when they come more often. If you have been asked to check your blood pressure at home, write the readings down with the date and time and take the notes with you. And keep track of the baby's movements: a baby that is short of nourishment usually goes quiet.

Signs that cannot wait for the next appointment

By the time pre-eclampsia makes itself felt, it is no longer at an early stage. Seek medical advice the same day, or go to the maternity unit if no appointment is available, if you develop:

• a severe headache that does not settle with paracetamol and rest;
• changes in vision — blurring, floaters, flashing lights, a missing patch of the visual field, double vision;
• pain under the right ribs or in the pit of the stomach, particularly if it comes on in the evening and is unrelated to meals;
• nausea and vomiting starting for the first time in the second half of pregnancy;
• rapid swelling of the face, eyelids and hands — a ring that will not come off, shoes that will not fasten;
• a sudden gain in weight, more than a kilogram over a few days;
• a noticeable drop in the baby's movements.

Pain under the right ribs deserves a separate mention: it is easily mistaken for heartburn or indigestion, and it can be the first sign of HELLP syndrome — a combination of red cells breaking down, liver damage and falling platelets. It develops quickly and is not always accompanied by high blood pressure.

Call an ambulance (in Spain, Italy, Portugal, Poland and Ukraine, 112) if a pregnant woman, or one who has recently given birth:

• has a seizure or loses consciousness;
• becomes suddenly breathless, cannot lie flat, or has blue lips;
• has severe chest or abdominal pain;
• starts bleeding from the vagina;
• becomes confused in her speech or does not know where she is.

Who is more at risk and what can be done in advance

The risk is clearly higher if there was already high blood pressure, kidney disease, type 1 or type 2 diabetes, lupus or antiphospholipid syndrome before the pregnancy, and also if pre-eclampsia occurred in a previous pregnancy. For these women a specific monitoring plan is drawn up at the booking appointment.

A moderate increase in risk comes from a first pregnancy, being over forty, marked obesity at the start of pregnancy, expecting twins or triplets, pre-eclampsia in a mother or sister, a long gap since the last pregnancy, and a pregnancy achieved through assisted reproduction. Each of these counts for little on its own, but two or more together are comparable to one of the major factors.

What genuinely works as prevention is low-dose aspirin, started around the twelfth week and continued until birth. It is the one measure with solid evidence behind it, and it reduces early pre-eclampsia, the most dangerous form, in particular. The decision and the dose belong to a doctor: aspirin is not taken in pregnancy without an indication. Women who eat few dairy products are also advised to take calcium.

Everything else is preparation before pregnancy: getting blood pressure and blood sugar under control, reviewing with a doctor any medicines that are unsuitable in pregnancy, and working on weight. Bed rest, salt restriction and diuretics, recommended for decades, do not prevent pre-eclampsia and are harmful during pregnancy.

How the diagnosis is confirmed

It starts with blood pressure. A reading of 140/90 mmHg or above is considered significant once it has been confirmed by a repeat measurement: a single spike in a consulting room is not yet a diagnosis. It is taken sitting, after a few minutes of rest, with a cuff of the right size for the arm.

Next comes the urine. A dipstick gives only a rough answer, so a positive result is followed by a precise measurement, the ratio of protein to creatinine in a single sample. One important qualification: pre-eclampsia is now also diagnosed without protein in the urine, when raised blood pressure is accompanied by damage to other organs. There is no need to wait for proteinuria before confirming it.

Blood tests show what is invisible from the outside: platelets, liver enzymes, creatinine and sometimes markers of red cells breaking down. There is also a test for placental growth factor, a protein made by a healthy placenta. A low level points to trouble, while a normal level at certain stages of pregnancy makes it possible to set the diagnosis aside with reasonable confidence and avoid an unnecessary admission.

On the baby's side there are ultrasound scans measuring size and the amount of amniotic fluid, doppler studies of the cord and uterine vessels, and a recording of the heart rate. Slowed growth and poor flow in the cord are as much part of the picture of pre-eclampsia as the numbers on the monitor.

Treatment and the timing of birth

After the diagnosis the woman is referred to hospital, at least for an initial assessment. What follows depends on severity: mild disease can be watched at home with frequent visits, severe disease means staying in hospital until the birth.

Blood pressure is lowered with medicines. Beta blockers, calcium channel blockers and centrally acting drugs are used — the ones best studied in pregnancy. The aim is not normal numbers at any cost but protecting the mother from stroke and other complications: too sharp a fall worsens the flow through the placenta. ACE inhibitors, angiotensin receptor blockers and diuretics are not used in pregnancy.

In severe pre-eclampsia, and when seizures threaten, magnesium sulphate is given by drip. It roughly halves the risk of eclampsia and remains the main treatment once a seizure has occurred. If the birth is going to be preterm, a steroid is given a day or two beforehand to speed up the maturing of the baby's lungs.

The timing of birth is always a balance between two risks. When the condition is stable, the pregnancy is usually carried to around thirty-seven weeks; waiting beyond that gains nothing. If things deteriorate — pressure climbing, platelets falling, the baby struggling — the birth is brought forward, sometimes considerably. The route of delivery is a separate decision: pre-eclampsia by itself is not a reason for a caesarean, and in a settled situation labour is often induced and managed vaginally.

The danger does not end with the birth

This is the part women are warned about least. In most cases blood pressure stays high for several more days and often peaks between the third and the sixth day, by which time the woman is at home. More than that, pre-eclampsia and eclampsia can begin for the first time after the birth, in a woman whose pregnancy was uneventful. A headache, visual disturbance, pain under the ribs or a seizure in the first weeks after birth therefore call for the same urgency as they would have before it.

In practice: do not give up blood pressure checks after going home, take the readings on the agreed days, and attend the follow-up appointments. Many women carry on with blood pressure tablets for a few more weeks, and these are withdrawn gradually, guided by the readings rather than by how one feels. Breastfeeding is not a barrier: there are medicines compatible with it and a doctor will choose them.

One more detail: if blood pressure is still high, ask which painkillers to use after the birth. Non-steroidal anti-inflammatory drugs hold on to fluid and push blood pressure up, so paracetamol is preferred in this situation.

What it means in the longer term

Pre-eclampsia is not an episode to be forgotten. It roughly doubles the likelihood of high blood pressure, heart attack and stroke in the decades that follow: the illness brings to light a predisposition that would otherwise have been discovered late. It is worth having blood pressure, weight, blood sugar and cholesterol checked once a year, and mentioning that pregnancy to a doctor even long afterwards.

Whether it happens again in a future pregnancy depends on how severe and how early the first episode was. After mild, late pre-eclampsia most women go through the next pregnancy without it. Either way, it is worth discussing a future pregnancy in advance: this is a case where prevention is started in the first weeks rather than when the numbers appear.

Online consultation

An online appointment is useful at two points. Before pregnancy and in its early weeks, to go through your history with a doctor: whether there has been high blood pressure, kidney disease, diabetes or an autoimmune condition, and how previous pregnancies went. That is what a decision on prevention and on how closely you need to be watched is built from.

The second point is during the pregnancy itself, when a question comes up and the next appointment is still far off. The doctor will go through your home blood pressure diary, explain what the test results mean, and help you tell the ordinary swollen legs and tiredness of pregnancy from the signs that mean going to hospital today. Have your dated blood pressure readings, recent blood and urine tests, scan reports and list of medicines to hand.

What an online consultation cannot replace is having your blood pressure taken, your urine tested and being examined. If the doctor says you need to be seen in person, that is not excessive caution: in pre-eclampsia the timescale is sometimes measured in hours.

This material is for information only and does not replace medical advice.