Do ultrasounds misdiagnose viable pregnancies as miscarriages?

Early ultrasounds have been used to detect pregnancy viability for the last 20 years.  Now shocking research published by Jeve et al. suggests many pregnancies diagnosed as miscarriages using ultrasonography may be misdiagnosed- leading to the early termination of wanted, viable pregnancies.

When miscarriage is suspected, current practice involves an early ultrasound.  Several measurements are used to diagnose miscarriage, which Jeve et al. argue are outdated.  The size of the gestational sac, embryo crown to rump length and cardiac activity are all measured by an initial and a follow up ultrasound (within 7-10 days).  However, variability in measurements and imprecision of instrumentation/ sonographers can lead to misdiagnosis.

The researchers found that even the most precise measurements: empty gestational sac with a diameter larger than 25 mm and absent yolk sac with mean gestational sac diameter ≥ 20 mm, may misdiagnose miscarriage in 4 out of every 100 cases.

The only conclusive criterion to diagnose miscarriage is the spontaneous expulsion of pregnancy tissue.  The researchers highlight the need for the development of new standards of miscarriage diagnosis by ultrasound in early pregnancy.  A zero false positive rate should be the goal.