A life-saving test for preeclampsia

Preeclampsia (PE) is a life-threatening disease of pregnancy, which causes high blood pressure, organ damage, and impairment in mothers and babies.

Until recently, diagnosis of PE relied on interpretation of clinical signs such as elevated blood pressure and protein in a mother’s urine. But these symptoms are also indicators of diabetes and kidney diseases. Such clinical diagnosis was unreliable, picking up only 20% of adverse events and producing a high level of false positives.

Now a test, developed by Oxford University researchers, accurately identifies women at risk of developing the disease.

‘PE is caused by an abnormality in the placenta’, explains lead researcher Professor Manu Vatish. ‘With the help of Roche Diagnostics, and obstetric and clinical bio-chemistry teams from the Oxford Universities Hospital Trust, we developed and trialed a diagnostic test that picks up the presence of two molecules produced by the placenta in the mother’s blood. The respective levels of these molecules tell us which women are likely to develop the disease and those that are extremely unlikely to develop it within the next week. The test has a 70% positive predictive value and a very low rate of false negatives.’

‘The potential benefit of the test is enormous,’ Vatish continues. ‘In the UK, PE requires that a woman is admitted to hospital for monitoring. Ultimately, the removal of the placenta is required to prevent eclampsia (fitting and organ failure) and save mother and baby. This often involves early delivery of the baby by caesarean or induction, which can negatively affect their health.’

‘The new test means that we can direct health resources to monitoring and treating ‘at risk women’. And women who are at little risk of PE are not admitted to hospital or subjected to unnecessary treatment.’

The test was first developed in 2018 and was rapidly adopted by Oxford Hospitals and across the Thames Valley. It is now offered by 90% of hospitals in the UK, has been approved by the National Institute of Clinical and Healthcare, and is funded for use across the NHS by the MedTech Funding Mandate.

It is now also being used internationally including Brazil, South Africa, Germany, Portugal. And the team has also developed a clinical protocol to ensure that health staff using it anywhere in the world will achieve accurate results.

‘It’s fantastic that the test has been adopted so quickly in the UK and further afield,’ continues Vatish. ‘But its potential to improve health outcomes in low-resource contexts is particularly significant.

‘Low-income countries will be able to direct scarce resources to those women who require treatment. And women who are not at risk can avoid an expensive, unnecessary and worrying trip to hospital, and the attendant loss of income and care capacity this may involve. We’re currently talking to the Gates Foundation about the potential to include the test in its strategy to tackle pre-eclampsia in low-income countries.’

Dr Sofia Cerdeira was also involved in the development of the new test. ‘One of the things that surprised and delighted us about rolling out the test’, she adds, ‘was how rapidly other departments, commercial companies, NHS bodies, and others recognised the potential of the test – and the efforts they made to help us take it to trial and implementation. It showed the potential of collaboration across diverse sectors to achieve positive health results.’

Manu Vatish ends: ‘The test is probably the most significant innovation in pregnancy care for twenty years and we’re delighted to see how rapidly it has moved to international implementation. We hope it will be adopted even more widely in the coming years and will make a real difference to outcomes for mothers and babies worldwide.’

Professor Manu Vatish is full Professor of Obstetrics and Consultant Obstetrician at the Nuffield Department of Women’s and Reproductive Health

Dr Sofia Cerdeira is NIHR Academic Clinical Lecturer in the Nuffield Department of Women’s and Reproductive Health

Other team members

Professor Tim James is a full Professor of Biochemistry and Head Biomedical Scientist for Clinical Biochemistry at Oxford

Funder: Roche Diagnostics