Study confirms single blood test can help identify pre-eclampsia risk

Tommy’s researchers say their findings should make the test more accessible to women and birthing people around the world

A single blood test is enough to help identify women and birthing people who are most at risk of developing severe pre-eclampsia and should be rolled out more widely, say Tommy's researchers.

The study was a follow-up to the PARROT trial, which looked at the effectiveness of a test to measure the amount of a substance called placental growth factor (PlGF) in the blood during pregnancy.

The PARROT trial found the test could help work out which women with symptoms of pre-eclampsia were most at risk of developing severe complications from the condition. PlGF testing also helped to reduce the time it took to diagnose pre-eclampsia.

In the new PARROT-2 study, also funded by Tommy’s and The Jon Moulton Charity Trust and published in The Lancet, the researchers found there was no benefit from repeating the test throughout pregnancy.

They say their findings should help to make the test more accessible and reduce the harm caused by pre-eclampsia.

PARROT-2 involved 1,252 women around the UK with suspected pre-eclampsia before 37 weeks of pregnancy.

The researchers found that if a woman’s first test showed an abnormal level of PlGF, that was enough to identify her as needing further monitoring and care for pre-eclampsia symptoms. There was no extra benefit from repeating the test as the pregnancy progressed.

Although extra tests enabled pre-eclampsia to be diagnosed more quickly, that did not lead to better outcomes for mothers or babies.

The researchers say: “[T]here is now a clear evidence base for implementation of initial PlGF-based testing, but without the necessity of higher costs associated with repeat PlGF-based testing.

“These results should therefore lower the barriers to more widespread, equitable adoption of initial PlGF-based testing, improving maternal health outcomes globally.”

Pre-eclampsia is a common and potentially serious complication of pregnancy, which in rare cases can cause the death of the mother or the stillbirth of her baby.  

Women with symptoms of pre-eclampsia may need to be admitted to hospital for treatment and monitoring. 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.

However, most cases of pre-eclampsia are mild and have no effect on the pregnancy.

Kath Abrahams, Chief Executive of Tommy’s, said: 

“This important study funded by Tommy’s and The Jon Moulton Charity Trust is a significant and positive step forwards in the drive to reduce the harm caused by pre-eclampsia.

“Following the breakthrough made by the previous Tommy’s funded PARROT study, we hope it will pave the way for PlGF testing for all women and birthing people who are thought to be at risk of pre-eclampsia, so that those most in need can be offered vital extra monitoring and support.”