Comparison of ultrasound criteria used to diagnose pregnancy loss

Measurement	Number of participants	Crown-rump length (without cardiac activity)	FPR	Mean gestational sac diameter	FPR
Initial studies^[1,2]	707 consecutive pregnancies	5 mm	Not available	16 mm	Not available
2011 prospective cross-sectional study^[3] (less stringent)	1060 total consecutive patients	6 mm	0	≥21 mm	0
2013 Society of Radiologists in Ultrasound^[4] (more stringent)	Combination of the previous studies	7 mm	0	≥25 mm	0

FPR: false-positive rate.

References:

Brown DL, Emerson DS, Felker RE, et al. Diagnosis of early embryonic demise by endovaginal sonography. J Ultrasound Med 1990; 9:631.
Pennell RG, Needleman L, Pajak T, et al. Prospective comparison of vaginal and abdominal sonography in normal early pregnancy. J Ultrasound Med 1991; 10:63.
Abdallah Y, Daemen A, Kirk E, et al. Limitations of current definitions of miscarriage using mean gestational sac diameter and crown-rump length measurements: a multicenter observational study. Ultrasound Obstet Gynecol 2011. 38:497.
Doubilet PM, Benson CB, Bourne T, et al. Diagnostic criteria for nonviable pregnancy early in the first trimester. N Engl J Med 2013; 369:1443.

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