Pre-eclampsia is a condition which is specific to pregnancy in which two of the three classical symptoms are present. They are:
1 A raised blood pressure,
2 Swelling of the feet, ankles or hands,
3 Protein in the urine.
More recently a fourth symptom, excessive weight gain, has been added to the above triad. This is not in fact a sign of pre-eclampsia, although it is nearly always a predisposing factor and a warning sign to which the incidence of pre-eclampsia can be directly related.
The cause of pre-eclampsia is still unknown despite a great deal of research. One aspect of the care of the pregnant woman in the antenatal clinic is always directed towards the prevention of preeclampsia.
Pre-eclampsia very seldom occurs before the 20th week of pregnancy, and is nearly always associated with extra weight gain. The essential change is a rise in blood pressure, but this is frequently accompanied by oedema. Or swelling, of the ankles and feet as well as the hands and often the face. Oedema of the feet is easily recognizable because not only do shoes become tight, but the swollen part of the foot can be indented quite easily by pressing with the finger. Swelling of the hands is usually noticed when rings become too tight for comfort and have to be removed, and women usually complain of stiffness in the fingers or pins and needles in the hands, especially early in the morning.
Swelling of the face is nearly always part of the generalized weight gain, but oedema can be recognized by the general puffiness, especially around the eyes and neck.
The normal blood pressure in a healthy woman of 2 5 is 120/70 mm. of mercury and does not alter greatly in normal pregnancy. The upper figure is the systolic blood pressure and the lower figure the diastolic blood pressure. The diastolic figure is the most important reading, because changes in this indicate a fundamental alteration in the body. The systolic blood pressure varies with emotion and exercise.
In pre-eclampsia the blood pressure rises until the diastolic pressure, which should normally be in the region of 60 or 70, has risen to 90.
As a result of a raised blood pressure protein is shed from the kidneys and can be detected in the urine. Routine urine tests are performed at every antenatal.visit during pregnancy to detect the presence of sugar, ketones and protein. Pre-eclampsia is one of many reasons why protein is found in the urine during pregnancy.
Pre-eclampsia develops slowly and insidiously; the signs appear long before the symptoms, and can be detected by vigilant antenatal care long before the woman notices any abnormality. The importance of regular antenatal visits cannot be over-emphasized, since it is at these visits that the doctor is able to detect the very earliest changes which might, if unchecked, lead to pre-eclampsia, and he is then able to give advice and institute treatment to prevent its onset. The condition can almost always be avoided if the pregnant woman understands the importance of antenatal care, keeps her antenatal appointments religiously and carries out her doctor’s instructions, especially those regarding her diet.
The reason for its development is not properly understood. A certain amount of swelling of the feet and ankles is normal in nearly every pregnancy, especially in the last 6 or 8 weeks. This usually appears during the day and generally disappears during the night, so that the feet and ankles have returned to normal by morning. This amount of swelling should not give rise to concern but ought to be mentioned to the doctor at the next antenatal visit. Some women have quite severe swelling of the ankles and also of the hands, abdomen and face without developing pre-eclampsia. Other women may develop a raised blood pressure without having any swelling of the feet or hands. It is normal for the blood pressure to fall in the early stages of pregnancy and to rise again at about the 20th week. There may be a further small rise in blood pressure towards the expected date of delivery and these minor changes in blood pressure are no cause for concern. The normal diastolic blood pressure of the non-pregnant woman, which is in the region of 70, may fall to 60, or even. 50, in the first 12 weeks of pregnancy, rising again to about 70 by the 20th week of pregnancy. Further small rises may occur so that by the 36th week of pregnancy the blood pressure may have reached 80 or even 85. All these changes will be carefully recorded by the doctor, but do hot cause any anxiety.
If the development of pre-eclampsia is allowed to continue unchecked the blood pressure will rise further and the oedema will increase. Headaches, especially over the eyes and across the forehead, begin, rapidly become more severe and do not respond to aspirin or the normal analgesics. Later the eyes are affected by blurring of vision and still later by the presence of flashing lights. Persistent headache and blurring of vision are very serious signs and must be reported immediately. This does not mean that every headache should be reported to the doctor but only those as described above which fail to respond to the usual remedies or those associated with persistent disturbances of vision.
If pre-eclampsia has developed then the treatment is admission to hospital, followed by bed-rest, sedation, daily urine tests, blood pressure taken twice daily, observation of oedema and an accurate fluid balance chart. These simple measures usually control the condition but if they fail then treatment with drugs may be necessary. In very exceptional instances the condition continues to get worse despite rest and treatment and .it may then be necessary either to induce labour before term or to perform Caesarean section.
Pre-eclampsia in itself does not do any lasting harm to the pregnant woman, so long as she is properly and efficiently treated. After delivery the swelling of the legs and hands goes, blood pressure gradually returns to normal although it may take several months, the kidneys return to their normal function and the protein will disappear from the urine. Untreated pre-eclampsia, however, may develop into eclampsia, which is extremely dangerous but, as a result of modern antenatal care, is now a rare condition.
The real danger of pre-eclampsia is to the unborn baby. It has been estimated that in Britain approximately 7 per cent of women having their first babies and 3 per cent of women having subsequent babies suffer from pre-eclampsia. All in all a total of almost 5 per cent of all pregnant women develop the condition, sometimes with disastrous results to their babies. The danger to the baby varies directly with the height of the mother’s blood pressure. Premature labour, either spontaneous or induced, results in a high proportion of small babies so that on an average 10 per cent of these babies fail to survive; that is i child in every 10 dying from a disease that is nearly always preventable. What a sin and what sorrow!