Pre-eclampsia is a disease unique to pregnancy. It is much more than just blood pressure and when we assess women who are suspected of having it, several investigations are done to establish its presence and severity.
In addition to high blood pressure, the other main screening test is to check the urine. The kidneys become 'leaky' and in pre-eclampsia there is protein (also known as proteinuria). You will see that it is sometimes documented as +, 2+, or 3+.
This is determined by dipping a piece of paper into the urine and the colour change suggests the relative concentration of the urine. To strictly diagnose pre-eclampsia, we need to know the exact amount of proteinuria over 24 hours and this is one investigation we do if it is suspected. Greater than 0.3g is significant.
Pre-eclampsia doesn't just affect the blood pressure and kidneys, it affects almost every organ system of the body. In the milder forms, it might just be the kidneys that are affected to any serious degree, hence proteinuria is the only other sign.
If pre-eclampsia is more severe, it can cause headaches, flashing lights before the eyes, abdominal pain as well as making you feel very jittery.
When does eclampsia occur?
If severe pre-eclampsia is not treated or if it develops very quickly, then eclampsia may occur. This is when a woman has a seizure (fit). Usually the BP is very high and if the baby is not yet born, it becomes distressed.
There is a serious risk of stroke in the mother because of the excessively high BP. Fortunately, eclampsia is rare as pre-eclampsia is usually picked up and treated.
Women with established pre-eclampsia have overall about a 1% chance of having an eclamptic seizure. In about half of the women who suffer eclampsia, it occurs after the baby is born, usually within 24 hours of delivery.