The current ultrasound test to diagnose miscarriage in early pregnancy is based on limited evidence, raising questions about its reliability, according to a new paper published by researchers at Queen Mary, University of London.
The researchers say that there is an urgent need to conduct a large-scale study for us to be confident that diagnosis of miscarriage is correct in every case using the ultrasound measurements.
When a miscarriage is suspected, the standard test is an ultrasound scan to look for the presence of an embryo in the pregnancy sac, to measure the length of the embryo and look for signs of heartbeat. Doctors may also look at symptoms such as bleeding and may test women’s blood for levels of pregnancy hormones.
If a miscarriage is confirmed the woman and her doctor can choose to wait and let the miscarriage progress naturally, or choose a medical or surgical intervention to speed up the process, and for that reason, accuracy is vital.
The paper examined all relevant evidence on the diagnosis of miscarriage using an ultrasound scan. For the first time, the researchers assessed the quality of each study and collated the results. They found that the studies were very few, conducted more than a decade ago and involved small number of women. The results highlighted gaps in the current evidence and raised questions about the reliability of the test in diagnosing miscarriage.
Dr Shakila Thangaratinam, Senior Clinical Lecturer at Queen Mary, University of London, led the study. She said: “When we’re testing to see if someone has a healthy pregnancy or not, we want to be absolutely confident that the test is reliable to avoid making a misdiagnosis. Our paper raises concerns about the gaps in evidence.
“We need to prioritise this area of research and do a large, good quality study so that we can be confident that ultrasound scans are highly accurate in diagnosing miscarriage. Until then, there is a need to review the existing guidelines and for women and their doctors to take a cautious approach until miscarriage is confirmed beyond doubt.”
Full paper: Accuracy of first-trimester ultrasound in the diagnosis of early embryonic demise: a systematic review. Jeve Y, Rana R, Bhide A, Thangaratinam S. Ultrasound Obstet Gynecol 2011; DOI: 10.1002/uog.10108
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