What gestational measurement suggests a failed pregnancy when the crown-rump length (CRL) is greater than 7 mm?

When the crown-rump length (CRL) exceeds 7 mm in an early pregnancy and there is no detectable heartbeat, it is a strong indicator of a failed pregnancy, specifically a missed abortion. At this stage of development, the embryo is expected to display signs of viability, including a detectable cardiac activity if the CRL is in the expected range for gestational age. If the heartbeat is absent at this size, it suggests that the embryo is not developing properly and raises concerns about the viability of the pregnancy.

No visible embryo, although concerning, is not as definitive as the lack of a heartbeat when the CRL is over 7 mm, as visualization can sometimes be affected by factors such as gestational age estimation or poor imaging conditions. Irregular sac shape and fluid accumulation can indicate complications but do not specifically correlate with the criteria for confirming a failed pregnancy based solely on CRL and heartbeat assessment.