Pre-eclampsia is diagnosed if both high blood pressure and protein in the urine are discovered by a GP or midwife during a routine antenatal appointment.
Many pregnant women with pre-eclampsia will not notice they have it. Only the GP or midwife will pick it up. However, if you notice any of the symptoms, see your GP.
Blood pressure
Blood pressure is monitored throughout your pregnancy at regular antenatal screenings.
Blood pressure is a measure of the force of the blood on the walls of the arteries (main blood vessels) as the blood flows through them. It is measured in millimetres of mercury (mmHg) and recorded as two figures:
- systolic pressure, which is the pressure when the heart beats and squeezes blood out
- diastolic pressure, which is the pressure when the heart rests in between beats
Your GP or midwife will use a sphygmomanometer to measure blood pressure (a device with an inflatable cuff and a scale of mercury as a pressure gauge). The systolic reading will be taken first, followed by the diastolic reading. If, for example, the systolic blood pressure is 120mmHg and the diastolic blood pressure is 80mmHg, overall blood pressure will be 120 over 80, which is commonly written as 120/80.
High blood pressure during pregnancy is usually defined as a systolic reading of 140mmHg or more, or a diastolic reading of 90mmHg or more. Severe hypertension is a systolic reading of 160mmHg or more, or a diastolic reading of 110mmHg or more.
Urine tests
A urine sample is usually requested at every antenatal appointment. This can easily be tested for protein using a dipstick. This is a strip of paper that has been treated with chemicals so it reacts to the presence of protein, usually by changing colour.
If the dipstick is positive for protein, your GP or midwife may ask for another urine sample to send to a laboratory for further tests. This could be a single sample of urine, or you may be asked to provide several samples of urine over a 24-hour period. These can be used to determine exactly how much protein is being lost through your urine.
Further tests
You will need more frequent antenatal appointments if you have either high blood pressure or protein in your urine. If symptoms are severe or get worse, you may be admitted to hospital for closer observation. Read more information about treating pre-eclampsia.
