Healthy babies being lost after mothers wrongly told they have had miscarriages
Published 14/10/2011 | 08:41
HUNDREDS of women may be ending healthy pregnancies unnecessarily each year after being told wrongly that they have miscarried.
Researchers say that current guidelines are not always reliable in determining whether women who are in pain or bleeding have suffered miscarriages early in pregnancy.
Medical workers make judgments based on measurements of the embryo or its gestational sac, as seen on an ultrasound scan, which could be inaccurate, it is claimed.
Experts believe that new guidelines should include wider measurements for the foetus as well as encouraging a “watch and wait” strategy rather than telling worried women that they should undergo a medical abortion.
Prof Tom Bourne of Imperial College London, who led a study of more than 1,000 women, 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.”
Many women go to hospital in early pregnancy because they are bleeding or in pain, and doctors use ultrasound images to see if they have lost their babies. Under current guidance from the Royal College of Obstetricians and Gynaecologists, if the gestational sac appears to be empty and has a diameter of less than 20mm it is classed as an Intrauterine Pregnancy of Uncertain Viability.
A repeat scan at least a week later is recommended.
In addition, if the embryo measures less than 6mm from “crown to rump” and appears not to have a heartbeat then it may also be classed as a miscarriage. If doctors decide a woman has suffered a miscarriage, they will recommend she either undergoes surgery or has a medical abortion to remove the foetus. In the latest series of studies, published in the journal Ultrasound in Obstetrics, researchers found that the measurements in the guidance were not based on good evidence, and that different medical practitioners calculate them differently.
In Prof Bourne’s study, 1,060 women from hospitals across London were monitored after they were classified as having had a suspected miscarriage.
By the time of their routine scan at 11-14 weeks, some still had viable pregnancies suggesting that they had been falsely diagnosed.
“The researchers point out that two practitioners will often give different measurements for the same embryo, suggesting that the “safe cut-off” limits need to be “significantly increased”.
They say that women can safely wait another seven to 10 days for a scan before ending their pregnancy. “The anxiety associated with being uncertain about the status of a pregnancy is very significant, but should be balanced against the possibility of inadvertent termination which is surely the worst possible outcome for any woman,” they add.
Experts insisted that the correct diagnosis was made in the “vast majority” of cases but accepted that large-scale research was needed. Dr Tony Falconer, the president of the Royal College of Obstetricians & Gynaecologists, said: “The findings add to our knowledge of clinical practice and will be considered when we update our guidelines.”
Dr Mark Hamilton, a consultant gynaecologist at Aberdeen Maternity Hospital, added: “These papers reinforce the need for clinical staff to continue to exercise great care in the diagnosis of non-viable pregnancy to minimise the risk of misdiagnosis.
“Those working in early pregnancy assessment units should examine current protocols used in the diagnosis of miscarriage, including the time interval between scans. Where clinical circumstances permit, women should continue to be managed expectantly without the need for medical treatment or surgery until the diagnosis of non-viability is established with certainty.”