Aspiration and microscopy in the diagnosis of ectopic pregnancy

Objective: To compare Karman cannula aspiration followed by dissecting microscopy with suction curettage and permanent histology in obtaining and identifying chorionic villi. Methods: Karman cannula aspiration was performed before standard curettage for failed intrauterine pregnancies (N=22) or possible ectopic gestation (N=24). Dissection microscopy for chorionic villi was performed on aspirates before submission for permanent histology. Sensitivity, specificity, positive and negative predictive value of each method in obtaining and identifying villi was determined. Results: Overall, all methods were only moderately sensitive in detecting chorionic villi (50–76%). If failed intrauterine pregnancies were excluded, all methods had poor sensitivity (25–64%). However, if villi were detected, the positive predictive value of all methods was high (>80%). Conclusions: Karman cannula aspiration followed by dissecting microscope examination or permanent histology may offer an alternative to traditional curettage in the diagnosis of ectopic gestations. A larger trial to validate these findings seems justified.