PARROT : using placental growth factor to tell if women are at high risk of pre-eclampsia complications

Tommy’s researchers are looking at whether a simple blood test can identify women at risk of severe complications from pre-eclampsia.
  • Authors list

    Dr Louise Webster, Mr Paul Seed, Prof Lucy Chappell, Prof Andrew Shennan, Dr Kate Duhig

This project took place at our London centre which operated between 1995 and 2021. 

This project is now complete

Why do we need this research?

Pre-eclampsia is a condition that only happens during pregnancy. Mothers who develop it can suffer from high blood pressure, blood clotting, and problems with their liver and kidneys. It can also cause problems with the placenta, which can slow the baby’s growth, and in some cases can lead to stillbirth.

If a woman is diagnosed with pre-eclampsia, she may need to be admitted to hospital to have her blood pressure treated, and to be monitored closely whilst planning for safe delivery of the baby. Some women become unwell very quickly and need to have their baby delivered straight away. Others will need long stays in hospital so that they can be observed.

At the moment, we can’t always tell which women are most at risk of severe complications and need early delivery for the safety of themselves and the baby.

What happened in this project?

Placenta growth factor (PlGF) is a molecule made by the placenta which can be detected by a simple blood test. Previous studies have shown that women with very low levels of PlGF are more likely to develop severe pre-eclampsia, or have a stillborn baby. Women with normal PlGF levels are at low risk, and can return to normal antenatal care. Testing PlGF levels could mean that care is focused on the women that really need it, while those that don’t avoid long stays in hospital.

The PARROT trial studied whether testing PlGF could help doctors decide how best to treat women who are showing symptoms of pre-eclampsia. More than 1,000 women at 11 UK maternity units took part in the trial. The results of the study showed that the PlGF blood test speeds up the diagnosis of pre-eclampsia, and helped to determine which women are at most risk of developing severe complications.

Our researchers have now begun the PARROT-2 trial, to understand whether repeating the PlGF blood test throughout pregnancy will help doctors to better monitor mothers at risk of pre-eclampsia.

What difference will this project make?

The results from the PARROT study have led to NHS England making the PlGF blood test more widely available. This will mean that doctors will be able to quickly identify the women at the greatest risk of developing severe pre-eclampsia. Ultimately, this will help mothers get the care they need, and help to improve the chances of a healthy birth for their baby.

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