TABLE 5.

Number of articles using ultrasound, and endometrial thickness (ET) measurement, to diagnose retained products of conception following early pregnancy loss or termination of pregnancy up to 14 weeks of gestation, per decade of article publication

	Year of publication	Number of publications	Number reporting ultrasound	Number reporting ET	Number reporting cut‐off value ET 15 mm
RCTs (N = 79)	<1979	1	0 (0%)	0 (0%)	0 (0%)
	1980–1989	4	2 (50%)	0 (0%)	0 (0%)
	1990–1999	15	12 (80%)	1 (6.67%)	1 (100%)
	2000–2009	27	24 (88.89%)	8 (29.6%)	5 (62.5%)
	2010–2019	32	28 (87.5%)	15 (46.9%)	11 (73.3%)
Observational studies (N = 169)	<1979	13	0 (0%)	0 (0%)	0 (0%)
	1980–1989	17	6 (35.3%)	0 (0%)	0 (0%)
	1990–1999	29	22 (75.9%)	1 (3.4%)	0 (0%)
	2000–2009	61	54 (88.5%)	17 (27.9%)	(70.6%)
	2010–2019	49	42 (85.7%)	14 (28.6%)	8 (57.1%)

Abbreviations: ET, endometrial thickness; RCT, randomized controlled trial.