Accuracy of diagnosis of retained products of conception after dilation and evacuation

Objective. Uterine re-evacuation samples taken in cases of suspected residua after curettage are occasionally negative for gestational tissue. We aimed at evaluating the occurrence of such postcurettage re-evacuation-negative samples and at exploring factors that may influence their occurrence. Methods. This was a cross-sectional comparative retrospective study of 69 consecutive women who underwent uterine re-evacuation for suspected postcurettage gestational remnants. Pathologic reports of samples drawn during re-evacuations were reviewed to determine whether the extracted tissue contained gestational tissue. The presence of factors that may influence the rate of a positive or negative sample (eg, sonographic findings, gestational age at initial procedure, and presenting symptom) was noted and compared between women with and without histologically verified remnants. Results. Twenty-eight (41%) of the re-evacuation samples were histopathologically positive for gestational remnants. Residual tissue was more commonly found when the initial evacuation was performed at a more advanced gestational age (>15 weeks). Women referred by emergency department attendants had significantly fewer positive samples. Normal expert sonographic examination practically excluded yielding samples. Conversely, no negative samples were preceded by sonographic reports mentioning residua. Conclusions. Most re-evacuation samples taken during a re-evacuation procedure for suspected residua are negative for gestational tissue. Parameters that are likely related to histologically confirmed gestational residual tissue are advanced gestational age at initial evacuation, level of the sonographer's skill, persistent bleeding as the presenting symptom, and a sonographic report specifically mentioning retained gestational tissue.