Lloydspharmacy.com Health - Pregnancy-induced high blood pressure (pre-eclampsia)

Reviewed by Dr Philip Owen, consultant obstetrician and gynaecologist

What is pre-eclampsia?

Regular checks of blood pressure, protein levels in the urine and water retention are necessary into the last trimester of pregnancy to prevent pre-eclampsia.

Up to 1 in 10 pregnant women develop raised blood pressure accompanied by the appearance of protein in the urine (proteinuria) and retention of excessive amounts of fluid in the body (oedema). It is not usually seen before the sixth month of pregnancy and most women develop the condition at the end of their pregnancy. However, only 1 out of 100 women will have the severe form of the condition.

Pre-eclampsia can also occur up to a week following delivery of the baby.

Why does this occur?

It is still not known why certain women develop high blood pressure during pregnancy.

Certain pre-existing conditions increase the risk of developing high blood pressure. They include:

first pregnancy
diabetes
essential hypertension (high blood pressure before pregnancy)
chronic kidney diseases
previous pregnancies affected by pre-eclampsia
carrying twins or triplets.

What are the symptoms?

Hypertension (high blood pressure)

Unless her blood pressure is very high, a woman will not be aware that it has increased. As a general rule a blood pressure greater than 140/90mmHg in pregnancy is considered to be raised.

Very high blood pressure (greater than 170/110mmHg)

Often accompanied by headaches and the appearance of flashing lights before the eyes. Measuring a woman's blood pressure is an essential part of any antenatal clinic visit.

Protein in the urine

This is detected by your doctor or midwife by using a special stick to dip into a clean sample of urine. There are other causes of proteinuria but pre-eclampsia is the cause with most significance for the mother and foetus.

Sudden or insidious weight gain with swollen hands, feet , face or other parts of the body

Some swelling is normal in pregnancy but it should prompt a woman to have her blood pressure and urine checked.

Pain in the right upper abdomen

May indicate involvement of the liver, which in severe cases can be complicated by an imbalance of the coagulation system that causes an increased or decreased ability of the blood to clot.

Headaches, fatigue, and pains in the upper abdomen

These are all symptoms of the more severe stage of the condition.

Pre-eclampsia is often subdivided into mild, moderate and severe depending on the level of blood pressure and the involvement of other organs in the disease process. In the worst cases, pre-eclampsia can develop into eclampsia, a situation where the mother has a convulsion. Fortunately, eclampsia is rare, but this is largely because women with pre-eclampsia are usually detected and treated before eclampsia can develop.

All the symptoms will disappear after the delivery and normally the blood pressure and protein level in the urine will be back to normal after a maximum of two weeks.

Treatment

The primary aim is to monitor the mother and the foetus closely. This may require hospital admission. Pre-eclampsia can, in severe cases, influence the placental function and diminish the flow of nourishment and oxygen to the foetus, which will slow its growth. Antihypertensive medicines of different groups are often used to reduce blood pressure.

If the woman's condition deteriorates and the foetus is at risk, the only solution is to deliver the baby either by induction of labour or by performing a Caesarean section.

Prevention

Monitoring of the woman's blood pressure and urine is essential. If hypertension is developing, it is vital to measure the blood pressure and test urine for protein regularly.

Giving women a small dose of aspirin (eg Nu-seals 75mg) throughout their pregnancy has been proposed as a preventive measure, but current research does not support this practice. There may still be very a small group of women at high risk of developing the disease who may benefit from aspirin.

Calcium supplementation is of uncertain benefit but may be of use for women with a high risk of pre-eclampsia.

The most recent development is in using antioxidants such as vitamin C and vitamin E to prevent pre-eclampsia. Research is at an early stage, although early results are promising.

Based on a text by Dr Vibeke Manniche

Last updated 02.06.2005