Fetal viability may be in question for some pregnant patients presenting to the ED. Conservative transvaginal US diagnostic criteria for a failed IUP include a crown-rump length of 7 mm with no cardiac activity; a mean GS diameter of ≥ 25 mm and no visible embryo; no heartbeat ≥ 2 weeks after a visualized GS without a yolk sac; no heartbeat ≥ 11 days after a prior documented GS with a yolk sac; and no heartbeat ≥ 2 weeks after a prior documented GS without a yolk sac.
Management and Disposition
Obtain gynecologic consultation and follow-up to confirm ED findings for patients whose fetal viability is in question. Consider repeat US to confirm the diagnosis in stable, asymptomatic patients. For patients with findings suspicious for but not meeting criteria for a failed IUP, refer for outpatient gynecologic evaluation and arrange repeat US in 7 to 10 days.
Indeterminate Viability. This fetal pole with a crown-rump length of 5.8 mm and no cardiac activity is consistent with indeterminate viability versus a failed IUP, which is diagnosed if crown-rump length is ≥ 7 mm and no cardiac activity. (Photo contributor: Kevin J. Knoop, MD, MS.)
Follow strict diagnostic criteria for failed IUP to minimize the possibility of a false-positive finding (ie, incorrectly diagnosing nonviability).
Failed Intrauterine Pregnancy. This enlarged gestational sac with no visible cardiac activity is consistent with a failed IUP if the mean gestational sac diameter is ≥ 25 mm. (Photo contributor: Lauren Oliveira, DO.)
Video 10-05: No Cardiac Activity
A failed IUP is diagnosed if CRL is ?7mm and no cardiac activity.