Accuracy of first-trimester ultrasound in the diagnosis of early embryonic demise: a systematic review.

OBJECTIVES

To evaluate, by systematic review of the literature, the accuracy of first-trimester ultrasound in diagnosing early embryonic demise.

METHODS

We searched MEDLINE (1951-2011), Embase (1980-2011) and the Cochrane Library (2010) for relevant citations. The reference lists of all known primary and review articles were examined. Language restrictions were not applied. Studies which evaluated the accuracy of first-trimester ultrasonography in pregnant women for the diagnosis of early embryonic demise were selected in a two-stage process and their data extracted by two reviewers. Accuracy measures including sensitivity, specificity and likelihood ratios (LRs) for abnormal and normal test results were calculated for each study and for each test threshold.

RESULTS

Eight primary articles with four test categories (18 2 × 2 tables), involving 872 women, evaluated the accuracy of ultrasound in diagnosing early embryonic demise. The lower limit of the 95% CI for specificity was > 0.95 in only two tests. These were an empty gestational sac with mean diameter of ≥ 25 mm and absent yolk sac with a mean gestational sac diameter of ≥ 20 mm (specificity, 1.00; 95% CI, 0.96-1.00 for both).

CONCLUSIONS

There is a paucity of high-quality, prospective data on which to base guidelines for the accurate diagnosis of early pregnancy demise. The findings are limited by the small number of studies and patients, the age of the studies, inclusion of symptomatic and asymptomatic women and variable reference standards for diagnosis of early pregnancy demise. Before guidelines for the safe management of threatened miscarriage can be formulated, there is an urgent need for an appropriately powered, prospective study using current ultrasound technology and an agreed reference standard for pregnancy success or loss.