The yolk stalk sign: evidence of death in small embryos without heartbeats

Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Ave, San Francisco, CA 94143-0628 USA.
Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine (Impact Factor: 1.54). 02/2010; 29(2):237-41.
Source: PubMed


The purpose of this study was to assess the positive predictive value for confirming early embryonic death in the clinical sonographic scenario wherein an embryo is identified without a visible heartbeat; the embryonic crown-rump length (CRL) is 5 mm or less; and the embryo is not immediately adjacent to the yolk sac.
A retrospective study of 882 first-trimester sonograms was performed among women who had an intrauterine pregnancy of uncertain viability based on 1 or more sonographic findings (eg, no visible heartbeat in an embryo with a CRL of < or =5 mm). Eight hundred six cases met the inclusion criteria.
Among the cohort of 806 cases, 520 (64.5%) had an identifiable embryo. One hundred fifty-nine of these embryos had no demonstrable heartbeat and a CRL of 5 mm or less. The CRLs of these embryos ranged from 1.7 to 5.4 mm. This cohort's sonograms were reviewed to determine whether there was a separation between the embryo and yolk sac. Twenty-one cases were discovered. Recall that as a retrospective study, no specific effort was made to show this finding. Thus, a computation of the sensitivity of this finding would result in an underestimate of indeterminate magnitude. All of these cases were subsequently proven to be failed pregnancies.
The positive predictive value of the "yolk stalk sign" in determining early pregnancy failure for an embryo with a CRL of 5 mm or less and no visible heartbeat was 100% in this cohort.

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    ABSTRACT: The purposes of this study were to assess a discriminatory "minimum menstrual age" (28 days + number of days elapsed between the first positive pregnancy test result and sonogram) for the diagnosis of early pregnancy failure when no embryonic/fetal heartbeat is seen and to compare minimum menstrual age dating with last menstrual period and sonographic dating. We conducted a retrospective study of 338 initial first-trimester sonographic examinations among women with suspected early pregnancy failure. A minimum menstrual age for each was calculated, and pregnancy outcomes were assessed. The predictive value of the minimum menstrual age for the pregnancy outcome was assessed at both 42 and 49 days and compared to that of dating by the last menstrual period and sonography. Among a study cohort of 338 patients, the average gestational age calculated by the last menstrual period was 53 days; by sonography, it was 50 days; and by the minimum menstrual age, it was 35 days (P < .01). All cases in which there was no sonographically detectable embryonic heartbeat above a minimum menstrual age of 42 days resulted in pregnancy failure. The minimum menstrual age is a conservative estimate of the gestational age, with an estimated positive predictive value of 100% for early pregnancy failure when no embryonic heartbeat is seen after 42 days. The minimum menstrual age can be combined with other existing diagnostic clues to predict early pregnancy failure with greater accuracy.
    Journal of ultrasound in medicine: official journal of the American Institute of Ultrasound in Medicine 11/2011; 30(11):1553-9. · 1.54 Impact Factor

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