What is the suggested mean gestational sac diameter indicative of a failed pregnancy?

A gestational sac diameter of greater than 25 mm is indicative of a failed pregnancy, particularly when no corresponding fetal pole or heartbeat is detected. This measurement serves as an important ultrasound criterion to assess the viability of an early pregnancy. As the gestational sac develops, it should generally contain a visible embryo with a heartbeat by certain gestational ages. When the sac size reaches a diameter of 25 mm or more without evidence of a fetal pole, it strongly suggests that the pregnancy is non-viable, as it often indicates that the normal growth and developmental processes have ceased.

Smaller sac diameters, such as those less than 25 mm, may still be compatible with a viable embryo in early pregnancy. Therefore, understanding the significance of the 25 mm threshold is crucial for the clinical evaluation of early pregnancy outcomes.