Failed early pregnancy
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Failed early pregnancy refers to the death of the embryo and therefore, miscarriage. The most common cause of embryonic death is a chromosomal abnormality.
Radiographic features
Ultrasound
Findings diagnostic of pregnancy failure
- crown-rump length (CRL) of ≥7 mm and no heartbeat on a transvaginal scan3
- mean sac diameter (MSD) of ≥25 mm and no embryo on a transvaginal scan3
- absence of embryo with heartbeat ≥2 weeks after a scan that showed a gestational sac without a yolk sac
- absence of embryo with heartbeat ≥11 days after a scan that showed a gestational sac with a yolk sac
- sac with no embryo and an MSD <12 mm on initial scan that fails to double in size on a scan ≥14 days later 2
- sac with no embryo and an MSD ≥12 mm on initial scan with no embryo heart activity on a scan ≥7 days later 2
- embryo (irrespective of crown-rump length) without cardiac activity on initial scan and on repeat scan ≥7 days later 2
- cessation of a previously documented cardiac activity of embryo (irrespective of crown-rump length)
Findings suspicious but not diagnostic of pregnancy failure
- crown-rump length (CRL) of <7 mm and no heartbeat
- mean sac diameter (MSD) of 16-24 mm and no embryo
- absence of embryo with heartbeat 7-13 days after a scan that showed a gestational sac without a yolk sac
- absence of embryo with heartbeat 7-10 days after a scan that showed a gestational sac with a yolk sac
- absence of embryo ≥6 weeks after last menstrual period
- absence of embryo when amnion seen adjacent to yolk sac (empty amnion sign)
- embryo present with amnion visible around it but no heartbeat (expanded amnion sign)
- small gestational sac in relation to the size of the embryo (<5 mm difference between mean sac diameter and crown-rump length)
- enlarged yolk sac (>7 mm)
Practical points
When there are findings suspicious for pregnancy failure, follow-up ultrasonography at 7-14 days to assess the pregnancy for viability is generally appropriate.
See also
-<a href="/articles/crown-rump-length">crown-rump length</a> (CRL) of ≥<strong>7</strong> mm and no heartbeat on a transvaginal scan</li>- +<a href="/articles/crown-rump-length">crown-rump length</a> (CRL) of ≥<strong>7</strong> mm and no heartbeat on a transvaginal scan <sup>3</sup>
- +</li>
-<a href="/articles/mean-sac-diameter">mean sac diameter</a> (MSD) of ≥<strong>25</strong> mm and no embryo on a transvaginal scan</li>- +<a href="/articles/mean-sac-diameter">mean sac diameter</a> (MSD) of ≥<strong>25</strong> mm and no embryo on a transvaginal scan <sup>3</sup>
- +</li>
References changed:
- 3. Shuchi K. Rodgers, Crystal Chang, John T. DeBardeleben, Mindy M. Horrow. Normal and Abnormal US Findings in Early First-Trimester Pregnancy: Review of the Society of Radiologists in Ultrasound 2012 Consensus Panel Recommendations. (2015) RadioGraphics. 35 (7): 2135-48. <a href="https://doi.org/10.1148/rg.2015150092">doi:10.1148/rg.2015150092</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/26562242">Pubmed</a> <span class="ref_v4"></span>
- 4. S E Rowling, B G Coleman, J E Langer, P H Arger, H L Nisenbaum, S C Horii. First-trimester US parameters of failed pregnancy. (1997) Radiology. 203 (1): 211-7. <a href="https://doi.org/10.1148/radiology.203.1.9122395">doi:10.1148/radiology.203.1.9122395</a> - <a href="https://www.ncbi.nlm.nih.gov/pubmed/9122395">Pubmed</a> <span class="ref_v4"></span>