The finding of a gestational sac within the endocervix has two differentials:  a cervical ectopic, and an inevitable miscarriage.  

On follow-up in this case, products of conception were passed soon after this ultrasound, and a subsequent scan showed an empty uterus and endocervix, confirming the diagnosis of miscarriage.

Nonetheless, this appearance should have a high index of suspicion for a cervical ectopic, which is a potentially more serious diagnosis, with risk of hemorrhage. Furthermore the presence of cardiac activity in an endocervical miscarriage is an unusual feature.  Therefore, despite the final diagnosis of an inevitable miscarriage in this case, this appearance should be managed as a cervical ectopic until proven otherwise.