Diagnostic accuracy of transvaginal ultrasound-measured endometrial thickness and serum hCG levels in detecting retained products of conception: a systematic review and meta-analysis.
Ying Li, Huaying Fang, Wenqin Xia et al.
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In 30 seconds
This systematic review and meta-analysis assessed endometrial thickness (EMT), serum human chorionic gonadotropin (hCG), and their combination for diagnosing retained products of conception (RPOC). Across 15 diagnostic studies involving 3,268 patients, combined testing had the highest reported accuracy: sensitivity 0.93, specificity 0.91, and AUC 0.96. Serum hCG alone (cutoff 50 mIU/mL) outperformed EMT alone (cutoff 8 mm), with AUCs of 0.92 and 0.84, respectively. Transvaginal ultrasound also had a higher AUC than transabdominal ultrasound (0.86 vs. 0.79).
Key findings
- Combined hCG and EMT testing yielded sensitivity 0.93, specificity 0.91, and AUC 0.96.
- Serum hCG alone at a 50 mIU/mL cutoff had sensitivity 0.89, specificity 0.87, and AUC 0.92.
- EMT alone at an 8 mm cutoff had sensitivity 0.72, specificity 0.86, and AUC 0.84.
- Transvaginal ultrasound had a higher AUC than transabdominal ultrasound (0.86 vs. 0.79).
Why it matters
RPOC diagnosis may be informed by both biochemical and imaging findings. In this pooled analysis, combining hCG with EMT performed better than either measure alone, while transvaginal ultrasound showed greater diagnostic accuracy than transabdominal ultrasound. These results provide comparative diagnostic evidence, but accuracy estimates do not by themselves establish effects on patient outcomes.
What to keep in mind
The authors note heterogeneity in EMT measurement and limited exploration of cutoffs; the abstract also reports heterogeneity analyses across studies.