A number of miscarriages may be being misdiagnosed, resulting in the termination of otherwise viable pregnancies.

-Team@CMHF

• The finding follows several recent reports of women being told that they had miscarried only to go on to have healthy babies. It suggests that existing guidelines on diagnosing miscarriage need to be updated.
• Around 20 per cent of pregnancies end in miscarriage, the majority occurring within the first five to six weeks of pregnancy. In many cases the embryo spontaneously aborts, resulting in heavy bleeding.
• In other cases women may experience some cramping or mild bleeding and an ultrasound will be performed to detect whether the embryo is still alive.
• Current criteria to diagnose miscarriage by ultrasound vary around the world.
1. In the UK, an empty gestational sac – the structure in which an embryo usually grows – with a diameter greater than 20 mm is classified as a miscarriage,
2. In the US a diameter of 16 mm is used.
• If a smaller sac is detected which appears empty, the woman will usually be advised to have a second scan seven to 10 days later. If the sac has not grown in that time it is assumed that the woman has miscarried.
• Once miscarriage has been diagnosed, many women are offered surgery or drugs to remove the contents of their uterus.

Unreliable cut-offs

• Tom Bourne of Imperial College London and his colleagues have published results suggesting that these common cut-offs to diagnose miscarriage may be unreliable, and that healthy pregnancies may show no measurable growth of the gestational sac over this time period.
• When the team analysed the data, they found that if the 16 mm cut-off had been used to diagnose miscarriage, 175 of 183 women would have been correctly diagnosed as having had a miscarriage or not, with eight incorrectly told they had miscarried when they had not. If the 20 mm cut-off had been used, 182 would have been correctly diagnosed either way, with one misdiagnosis. When a cut-off of 21 mm was used no misdiagnosis occurred.
• There’s no doubt that on the basis of one scan, the potential for misdiagnosis exists, says Bourne.
• Some women seeking reassurance with pain or bleeding in early pregnancy may be told that they have had a miscarriage, and choose to undergo surgical or medical treatment when the pregnancy is in fact healthy.

Updating guidelines

• Bourne believes that there is an urgent need to update current guidelines in the light of this new evidence.
• If you have a diagnosis of miscarriage based on a scan, repeat the scan in all cases, he says.
• While there’s always pressure to make a diagnosis, there is no harm in saying look we don’t know, come back in a week and let’s have another look
• However, he cautions that a balance must be struck between ensuring a correct diagnosis, and the mental stress caused to women by the continued uncertainty of knowing whether they remain pregnant or not.
• A recent review published by the Irish government identified at least 18 cases of women who had been incorrectly diagnosed as having miscarried between 2005 and 2010, and of these 75 per cent were advised to undergo surgery to remove the remains of their embryo.
• Healthcare professionals must receive the best training possible to ensure that they are competent in antenatal screening and diagnoses so that mistakes are avoided, says Tony Falconer, president of the UK’s Royal College of Obstetricians and Gynaecologists.

For further reading log on to :  http://www.newscientist.com/article/dn21048-improve-miscarriage-guidelines-to-prevent-misdiagnosis.html