Table 1.

Classification of spontaneous miscarriage at diagnosis in an observational study

Classification	Transvaginal bleeding (No/yes)	Endometrial thickness* (mm)	Products of conception
Complete miscarriage	No	<15	None
Incomplete miscarriage	No/yes	Any	Heterogeneous tissues (with or without a gestational sac) distorting the endometrial midline echo
Missed miscarriage	No/yes	Any	Fetal pole (crown-rump length >6 mm, no heart beat) or if crown-rump length ⩽6 mm with no change on rescan 7 days later
Anembryonic pregnancy	No/yes	Any	Gestational sac (diameter >20 mm, no embryonic pole or yolk sac) or if diameter ⩽20 mm with no change 7 days later

^*Endometrial thickness = maximum distance from one myometria–endometrial interface to another.