Table 1.

Classification of First Trimester Pregnancy Loss

Diagnosis	Characteristic
Complete pregnancy loss	Complete passage of products of conception
	Cervix closed
	Endometrial thickness typically < 15 mm
Incomplete pregnancy loss	Partial passage of products of conception
	Cervix open or closed
	Any endometrial thickness
	Tissue distorting central endometrial echo is heterogeneous and may contain a gestational sac
Delayed pregnancy loss	No tissue passage
(includes what were previously called blighted ovum, anembryonic pregnancies, missed abortions)	Cervix closed
	Gestational sac > 20 mm without evidence of fetal pole or yolk sac
	Gestational sac < 20 mm with no change in size over 7 days
	Fetal pole > 6 mm with no detectable fetal heart activity
	Fetal pole < 6 mm with no change over 7 days

Adapted from Jauniaux E et al.¹