Role of transvaginal sonography in the diagnosis of retained products of conception

Introduction The aim of this study was to evaluate the criteria of endometrial thickness to detect retained products of conception following first trimester spontaneous abortion or elective pregnancy termination. Methods This was a retrospective study on 116 patients who underwent uterine re-evacuation with a diagnosis of retained products of conception based on clinical and sonographic findings. Pathologic reports of samples obtained during re-evacuation were reviewed for the presence of gestational tissue. Endometrial thickness determined by transvaginal sonography and certain clinical features (gestational age and interval between initial curettage and re-evacuation, which may affect presence or absence of gestational tissue, parity, indication for initial curettage) were noted. The sensitivity and specificity of sonographic measurement of endometrial thickness for detecting retained products of conception were assessed. Results Histopathologic reports confirmed the diagnosis of retained products of conception in 66 of 116 patients (56.9%). Percentage of nulliparity and the time elapsed between initial curettage and re-evacuation were significantly high in patients with retained products of conception. The sensitivity and specificity of endometrial thickness greater than 13 mm for detecting retained products of conception were 85 and 64%, respectively. Conclusion An endometrial thickness of 13 mm or more, detected by transvaginal sonography, has the best diagnostic efficiency for detection of retained products of conception following first trimester spontaneous abortion or elective pregnancy termination.