TABLE 2.

Diagnostic tools for evaluating the presence of retained products of conception with their four most frequently used parameters

Diagnostic tool	Parameter	RCTs (N = 79)	Observational studies (N = 169)
Ultrasound		66/79 (83.5%)	124 (73.4%)
	Endometrial thickness	24 (36.4%)	31 (25.0%)
	Presence of gestational sac	15 (22.7%)	22 (17.7%)
	Intrauterine remains	13 (19.7%)	15 (12.1%)
	Uterus not empty	2 (3.0%)	15 (12.1%)
Clinical interpretation		32 (40.5%)	78 (46.2%)
	Not specified	14 (43.8%)	32 (41.0%)
	Bleeding	10 (31.3%)	32 (41.0%)
	Uterine size	3 (9.4%)	12 (15.4%)
	Expulsion of POC	5 (15.6%)	4 (5.1%)
Human chorionic gonadotropin		22 (27.8%)	59 (34.9%)
	Not negative	5 (22.7%)	22 (37.3%)
	Not specified	5 (22.7%)	12 (20.3%)
	Not <10 IU/L	3 (13.6%)	2 (3.4%)
	Decrease less than 50%	3 (13.6%)	4 (6.8%)
	No decrease	2 (9.1%)	7 (11.9%)
Visual inspection of tissue lost		3 (3.8%)	9 (5.3%)
	Not specified	2 (66.7%)	3 (33.3%)
	No (complete) expulsion of POC	1 (33.3%)	n.a.
	Examination of POC by staff	n.a.	3 (33.3%)
	No tissue documented as POC	n.a.	2 (22.2%)
Pathologic/histologic examination of tissue		0 (0%)	7 (4.1%)
	POC histologically confirmed	n.a.	5 (71.4%)
	Tissue obtained at curettage	n.a.	2 (28.6%)
Patients’ history		4 (5.1%)	5 (3.0%)
	Not specified	2 (50.0%)	4 (80.0%)
	No passage of POC	1 (25.0%)	n.a.
	Persistence of heavy bleeding	1 (25.0%)	n.a.
	Contractions, abdominal pain, bleeding	n.a.	1 (20.0%)
Other		3 (3.8%)	15 (8.9%)
	Not specified	2 (66.7%)	5 (33.3%)
	Ongoing pregnancy	1 (33.3%)	n.a.
	No complete abortion	n.a.	2 (13.3%)
	Other	n.a.	2 (13.3%)

Abbreviations: IU/L, international units per litre; n.a., not applicable; POC, products of conception; RCT, randomized controlled trial.

To aid clarity, the parameters presented are restricted to the four most commonly used. Hence, the total amount of articles reporting a particular diagnostic tool do not always correlate with the total number of articles applying one of the four relevant parameters.