Diagnostic Accuracy of Transvaginal Sonography in the Detection of Retained Products of Conception: A Cross-Sectional...

Background Retained products of conception (RPOC) constitute a clinically significant complication following spontaneous abortion, induced termination, or postpartum delivery, representing a notable contributor to maternal morbidity in resource-limited settings. Timely and accurate diagnosis is paramount to prevent life-threatening sequelae, including hemorrhage, sepsis, and intrauterine adhesive disease. This study aimed to evaluate the diagnostic accuracy of transvaginal sonography (TVS) in detecting RPOC among women of reproductive age, utilizing histopathological examination as the reference gold standard, with stratified analysis across age, gestational age, and symptom duration. Methodology This cross-sectional study was conducted at the Department of Obstetrics and Gynaecology, Bolan Medical Complex Hospital (BMCH), Quetta, Pakistan, over a six-month period from October 2022 to April 2023. A total of 205 women aged 15-49 years presenting with clinically suspected RPOC were enrolled through consecutive non-probability sampling. Following thorough clinical evaluation, all participants underwent transvaginal Doppler sonography utilising a 5-7 MHz endovaginal probe. Definitive diagnosis was established through histopathological examination of uterine curettings. Diagnostic performance indices - including sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall diagnostic accuracy - were calculated from the 2×2 contingency matrix and stratified across demographic and clinical subgroups. Intergroup comparisons of diagnostic accuracy across age, gestational age, and symptom duration strata were performed using the chi-square test, with a p-value of less than 0.05 considered statistically significant. Results Histopathological examination confirmed RPOC positivity in 195 participants (95.12%), while transvaginal sonography yielded positive findings in 168 participants (81.95%). The 2×2 contingency analysis identified 164 true positives, 6 true negatives, 31 false negatives, and 4 false positives. Overall, TVS demonstrated a sensitivity of 84.10%, specificity of 60.00%, PPV of 97.62%, NPV of 16.21%, and diagnostic accuracy of 82.93%. Stratified analysis revealed superior diagnostic performance among younger women aged 15-30 years (accuracy 84.03%), participants with gestational age exceeding 27 weeks (sensitivity 85.52%, specificity 75.00%, accuracy 85.00%), and those presenting within 48 hours of symptom onset (specificity 75.00%, accuracy 84.52%); however, none of the intergroup differences across age (χ² = 0.093, p = 0.7602), gestational age (χ² = 0.274, p = 0.6006), or symptom duration (χ² = 0.312, p = 0.5765) strata attained statistical significance on chi-square testing. Conclusion Transvaginal sonography demonstrates clinically acceptable sensitivity and diagnostic accuracy for RPOC detection, with performance optimised at advanced gestational ages and acute symptom presentation. However, the critically low NPV confirms that TVS cannot function as a standalone exclusionary diagnostic tool, necessitating mandatory histopathological corroboration in all sonographically negative yet clinically symptomatic cases within high-prevalence clinical settings.