Failed early pregnancy

Last revised by Dr Yuranga Weerakkody on 05 Mar 2022

Failed early pregnancy (sometimes termed embryonic demise) refers to the death of the embryo and therefore, miscarriage. The most common cause of embryonic death is a chromosomal abnormality.

  • crown-rump length (CRL) of ≥7 mm and no heartbeat on a transvaginal scan 3
  • mean sac diameter (MSD) of ≥25 mm and no embryo on a transvaginal scan 3
  • 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)
  • 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)

When there are findings suspicious for pregnancy failure, follow-up ultrasonography at 7-14 days to assess the pregnancy for viability is generally appropriate.

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Cases and figures

  • Case 1: with absent fetal heart beat
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  • Case 2
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  • Case 3
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  • Case 4
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