Some miscarriage tests 'unreliable'

Hundreds of viable wanted pregnancies are being lost to British women each year because of unreliable miscarriage tests, new research suggests.





The precise numbers are unclear but scientists believe there could be 400 errors every year with the potential to result in terminations.



This is more than the estimated 300 cot deaths reported each year in the UK.



Experts today called for more research and improved professional guidelines to minimise the chances of such tragedies occurring.



Pain or bleeding, or a previous history of miscarriage, may prompt doctors to carry out an ultrasound investigation early in pregnancy.



Common practice is to measure the size of the gestational sac and the embryo it contains.



If a sac of a certain size appears empty, or an embryo reaches a certain stage of development with no heartbeat, a diagnosis of miscarriage is made.



When there is doubt about the results, physicians are advised to re-measure the gestational sac seven to 10 days later.



If the sac does not grow during that time, it is assumed a miscarriage has occurred. A termination may then follow.



But according to the new findings, from a series of research papers published in the journal Ultrasound in Obstetrics, the margin of error is so high that some perfectly viable pregnancies are being lost.



One study revealed an up to 20% variation in the size of gestational sacs reported by different clinicians measuring the same pregnancies.



Professor Tom Bourne, from Imperial College London, who led a study of more than 1,000 women suspected of miscarrying, said: "Currently there is a risk that some women seeking reassurance with pain or bleeding in early pregnancy may be told they have had a miscarriage and choose to undergo surgical or medical treatment when the pregnancy is in fact healthy."



Criteria used to diagnose miscarriage varies. In the UK, one classification under Royal College of Obstetricians and Gynaecologists guidelines is an empty gestational sac measuring 20 millimetres or more. Alternatively, a foetal size of 6mm or more with no heartbeat may also indicate a miscarriage.



In the US, a smaller gestational sac threshold of 16mm is adopted. According to the research, this could result in even more wrong diagnoses.



Each year an estimated 500,000 women have miscarriages in the UK. Research suggests around 30% of these women undergo early ultrasound scans.



Prof Bourne and colleagues write in their paper: "Applying a cut-off for MSD (mean sac diameter) of 20mm could lead to 400 viable pregnancies potentially being misclassified, compared with approximately 300 'cot deaths' reported in the UK each year.



"These numbers are significant and relate to pregnancies that would be highly likely to reach term."



The researchers suggest diagnosing miscarriage on the basis of an empty sac measuring 25mm, or a foetal size of 7mm or more with no heartbeat.



Speaking at a briefing in London, Prof Bourne said a repeat scan should be undertaken 10 days after the first "in all cases".



However, he added: "It's the responsibility of the profession to put its house in order."



Another study, led by Dr Shakila Thangaratinam, from Queen Mary, University of London, indicated that current guidelines were based on old and unreliable data.



"The majority of ultrasound standards used for diagnosis of miscarriage are based on limited evidence," she said.



The experts agreed there was a need for new research involving larger numbers of patients.



Dr Tony Falconer, president of the Royal College of Obstetricians and Gynaecologists (RCOG), said: "The RCOG peer reviews its guidelines routinely and works with other organisations such as Nice (National Institute for Health and Clinical Excellence) to develop best practice advice for doctors. The findings from these papers add to our knowledge of clinical practice and will be considered when we update our guidelines.



"Miscarriage is an upsetting experience for anyone and all women who have had a miscarriage should have access to support from the NHS. Healthcare professionals must receive the best training possible to ensure that they are competent in antenatal screening and diagnoses so that mistakes are avoided."



Professor Jane Norman, director of the Tommy's Centre for Maternal and Foetal Health, University of Edinburgh, said: "In women in early pregnancy, it can often be difficult to confidently distinguish a very early ongoing pregnancy from a miscarriage. Most UK units will adhere to guidelines from the Royal College of Obstetricians (RCOG) on the management of early pregnancy loss in order to make this diagnosis.



"These new data show that following the current RCOG guidelines will give the correct diagnosis in the vast majority of women. They also provide some robust new evidence on which to further improve guidelines for diagnosis in this very important clinical condition."



Prof Bourne sought to reassure women who might be worried about the study findings.



"I don't think women should be anxious, but I do think we should get it right so we don't make any mistakes," he said. "What I'm not saying is that it's likely that someone who has had surgery for miscarriage has had a misdiagnosis of miscarriage."

PA

Life and Style
ebookNow available in paperback
ebooks
ebookA delicious collection of 50 meaty main courses
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Recruitment Genius: Senior Environmental Adviser - Maternity Cover

    £37040 - £43600 per annum: Recruitment Genius: The UK's export credit agency a...

    Recruitment Genius: CBM & Lubrication Technician

    £25000 - £27500 per annum: Recruitment Genius: This company provides a compreh...

    Recruitment Genius: Care Worker - Residential Emergency Service

    £16800 - £19500 per annum: Recruitment Genius: Would you like to join an organ...

    Recruitment Genius: Senior Landscaper

    £25000 - £28000 per annum: Recruitment Genius: In the last five years this com...

    Day In a Page

    Refugee crisis: David Cameron lowered the flag for the dead king of Saudi Arabia - will he do the same honour for little Aylan Kurdi?

    Cameron lowered the flag for the dead king of Saudi Arabia...

    But will he do the same honour for little Aylan Kurdi, asks Robert Fisk
    Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

    Our leaders lack courage in this refugee crisis. We are shamed by our European neighbours

    Humanity must be at the heart of politics, says Jeremy Corbyn
    Joe Biden's 'tease tour': Could the US Vice-President be testing the water for a presidential run?

    Joe Biden's 'tease tour'

    Could the US Vice-President be testing the water for a presidential run?
    Britain's 24-hour culture: With the 'leisured society' a distant dream we're working longer and less regular hours than ever

    Britain's 24-hour culture

    With the 'leisured society' a distant dream we're working longer and less regular hours than ever
    Diplomacy board game: Treachery is the way to win - which makes it just like the real thing

    The addictive nature of Diplomacy

    Bullying, betrayal, aggression – it may be just a board game, but the family that plays Diplomacy may never look at each other in the same way again
    Lady Chatterley's Lover: Racy underwear for fans of DH Lawrence's equally racy tome

    Fashion: Ooh, Lady Chatterley!

    Take inspiration from DH Lawrence's racy tome with equally racy underwear
    8 best children's clocks

    Tick-tock: 8 best children's clocks

    Whether you’re teaching them to tell the time or putting the finishing touches to a nursery, there’s a ticker for that
    Charlie Austin: Queens Park Rangers striker says ‘If the move is not right, I’m not going’

    Charlie Austin: ‘If the move is not right, I’m not going’

    After hitting 18 goals in the Premier League last season, the QPR striker was the great non-deal of transfer deadline day. But he says he'd preferred another shot at promotion
    Isis profits from destruction of antiquities by selling relics to dealers - and then blowing up the buildings they come from to conceal the evidence of looting

    How Isis profits from destruction of antiquities

    Robert Fisk on the terrorist group's manipulation of the market to increase the price of artefacts
    Labour leadership: Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea

    'If we lose touch we’ll end up with two decades of the Tories'

    In an exclusive interview, Andy Burnham urges Jeremy Corbyn voters to think again in last-minute plea
    Tunisia fears its Arab Spring could be reversed as the new regime becomes as intolerant of dissent as its predecessor

    The Arab Spring reversed

    Tunisian protesters fear that a new law will whitewash corrupt businessmen and officials, but they are finding that the new regime is becoming as intolerant of dissent as its predecessor
    King Arthur: Legendary figure was real and lived most of his life in Strathclyde, academic claims

    Academic claims King Arthur was real - and reveals where he lived

    Dr Andrew Breeze says the legendary figure did exist – but was a general, not a king
    Who is Oliver Bonas and how has he captured middle-class hearts?

    Who is Oliver Bonas?

    It's the first high-street store to pay its staff the living wage, and it saw out the recession in style
    Earth has 'lost more than half its trees' since humans first started cutting them down

    Axe-wielding Man fells half the world’s trees – leaving us just 422 each

    However, the number of trees may be eight times higher than previously thought
    60 years of Scalextric: Model cars are now stuffed with as much tech as real ones

    60 years of Scalextric

    Model cars are now stuffed with as much tech as real ones