Placental histopathology revisited

Abstract

There is little guidance on which placentas should be subjected to histopathology, how to conduct this investigation or how to evaluate the results. The aims of our study were to: (a) determine if requests for placental pathology adhered to local guidelines; (b) correlate clinical diagnosis with histological report; and (c) determine if the expertise of the pathologist influenced the report. Guidelines were established for requesting placental histology. Pathology reports during two 3-month periods were studied and inappropriate requests identified. The clinical diagnosis was compared with the pathological report. During the first 3 months, all examinations were performed by a general pathologist. During the second 3 months, a paediatric pathologist performed all the examinations. A histology scoring system was devised to standardise reports. Its application in the first and second study periods was compared. According to guidelines, 190 placentas should have been submitted for histology during the 6 months studied. One hundred and thirty-one placentas were actually sent (69% of possible total); 12/131 (9%) were inappropriate requests. In the first 3 months 51/79 (64%) of reports documented changes compatible with the clinical diagnosis compared with 44/52 (85%) in the second 3 months. The histology score increased significantly from the first period (mean 25, range 6–36) to the second period (mean 31, range 10–43) p <0.01.