Pre-eclampsia

What is pre-eclampsia?

Pre-eclampsia is a common complication of pregnancy that causes high blood pressure (higher than 140/90).

It is also known as toxaemia, pregnancy-induced hypertension and pre-eclamptic toxaemia.

The condition occurs in the last half of the pregnancy, or in the first few days after the baby is delivered. It disappears within a few weeks after the birth.

Pre-eclampsia can be mild or severe. If the condition gets so bad that the affected woman has a seizure, it is then referred to as ‘eclampsia’. Another severe form of the disease is called HELLP syndrome, which is an acronym for the combination of problems that can develop: Haemolysis (destruction of red blood cells), Elevated Liver enzymes and Low Platelets.

Some women who have had pre-eclampsia can get heart problems and kidney problems later in life.

What causes pre-eclampsia?

It is not known why some women develop pre-eclampsia, although there are some factors that seem to make certain women more at risk of getting the condition than other women. These risk factors include:

• a family history of pre-eclampsia
• pre-existing high blood pressure
• multiple pregnancy (such as twins or triplets)
• not having been a mother before.

There is no test that will predict who will get pre-eclampsia. There is no known way to prevent it.

What are the symptoms of pre-eclampsia?

When a woman develops pre-eclampsia, the muscles that surrounds her arteries are constricted instead of relaxed, making it hard for blood to flow through. This causes high blood pressure and reduces the blood flow to the liver, kidneys, eyes and brain. It also causes damage to the internal lining of the arteries, which leak fluid out into the tissues and cause swelling of the legs, hands and face.

Other symptoms of pre-eclampsia can include:

• excess protein in the urine (proteinuria)
• severe headaches
• changes in vision, including temporary loss of vision, blurred vision or light sensitivity
• pain in the upper abdominal, usually under the ribs on the right side
• nausea or vomiting
• decreased urine output
• decreased levels of platelets in the blood (thrombocytopenia)
• impaired liver function
• shortness of breath.

How does pre-eclampsia affect the unborn baby?

Arteries carrying blood to the baby are also affected by pre-eclampsia. If the condition is severe enough, the baby’s growth can slow down, the amount of fluid surrounding the baby is less than it should be, and there is a risk of the placenta separating from the uterus, causing bleeding (‘abruption’). All of these things can cause harm to the baby.

The health of the mother and baby is monitored regularly during the pregnancy. If the pre-eclampsia gets too severe, the birth may need to be brought forward, before serious harm is done.

How is pre-eclampsia treated?

There is no specific treatment for pre-eclampsia. While drugs can be used to safely lower the mother’s blood pressure to reduce the risk of her having a stroke, this will not stop the problem of the arteries constricting, and so will not stop the pre-eclampsia.

Treatment can also be given to try to prevent seizures, which are very rare, but can happen in cases of severe pre-eclampsia. If a woman is at risk of having a seizure, magnesium can be given intravenously to reduce the risk of seizure.

What happens in intensive care?

Women with severe pre-eclampsia or eclampsia are generally admitted to an intensive care unit (ICU) after their baby has been born so they can continue to receive treatment to lower their blood pressure. However, in cases where the mother has developed kidney failure or fluid in her lungs, she may need to go to an ICU before the baby is delivered.

In the ICU, the mother will be monitored closely to keep her blood pressure under control and reduce her risk of seizures. An indwelling urinary catheter will be used to measure urine output, and she will have regular blood tests and urine tests.

If the mother and baby are well enough, they will be brought together and maternity staff will help the mother to breastfeed the baby, if she wishes to do so. In most cases, the father and other relatives will also be encouraged to get involved in the care of the baby.

Once the mother no longer needs intravenous magnesium and her blood pressure can be controlled with tablets, she can move from the ICU to the post-natal ward of the hospital.

Useful links

• Australian Government, Dept of Health. Pregnancy, Birth and Baby – Pre-eclampsia
• Preeclampsia Research Laboratories (PEARLS). Preventing Pre-eclampsia

Publication details

Version 1.1. First published 2015. Next review 2023.