New blood test to help diagnose pre-eclampsia earlier

Until now, medics have had to use 'relatively imprecise' techniques to detect the potentially-lethal condition in pregnant women.

A blood test for pre-eclampsia is being rolled out by NHS England after a study showed it can help diagnose the potentially-lethal pregnancy condition earlier.

Experts say the new tool will help doctors and midwives who have had to use the same “relatively imprecise” techniques for a century.

Pre-eclampsia is suspected in around 10% of UK pregnancies, affecting approximately 80,000 women annually.

Complications can cause premature birth and, in extreme cases, can kill the mother and baby.

The condition usually occurs during the second half of pregnancy, from around 20 weeks, or soon after a baby is delivered, and is characterised in part by high blood pressure and protein in the mother’s urine.

Experts at King’s College London found that measuring a particular protein called placental growth factor (PlGF) in a woman’s blood, they were able to diagnose pre-eclampsia on average two days sooner.

Lucy Chappell, a professor in obstetrics at King’s, said: “For the last hundred years, we have diagnosed pre-eclampsia through measuring blood pressure and checking for protein in a woman’s urine. These are relatively imprecise and often quite subjective.

“We knew that monitoring PlGF was an accurate way to help detect the condition but were unsure whether making this tool available to clinicians would lead to better care for women. Now we know that it does.”

Professor Tony Young, national clinical lead for innovation at NHS England, said: “This innovative blood test, as set out in this new study, helps determine the risks of pre-eclampsia in pregnancy, enabling women to be directed to appropriate care or reduce unnecessary worry more quickly.

“The NHS, with partners in government, will be making this test more widely available across the NHS as part of our plans to ensure as many patients as possible can benefit from world-class health innovations.”

The King’s team studied 1,035 women with suspected pre-eclampsia from 11 maternity units across the UK.

The women were randomly split into two groups, one of which had the results of their PlGF test revealed to their medical teams.

Their results, which were published in the Lancet on Tuesday, showed the test reduced the average time to pre-eclampsia diagnosis from 4.1 days to 1.9 days.

Serious complications before birth, such as eclampsia, stroke, and maternal death, were reduced from from 5% to 4%.

There was no change in the age that the babies were delivered prematurely or in the likelihood of them developing complications.

Prof Chappell said: “The evidence shows that widespread PlGF testing could saves lives and it is fantastic news that NHS England agree.

“Many tests have come into practice without robust assessment. This time, we have evaluated this new test and shown that it improves care and outcomes for pregnant women and their babies.”