Frozen section of placental membranes and umbilical cord: an aid to early postpartum diagnosis of intra-amniotic infection.

Abstract

We devised a rapid frozen section (FS) assessment technique of placental tissues and performed the first rigorous assessment of FS relative to conventional workup. We evaluated 49 placentas with clinical/gross suspicion of intra-amniotic infection by FS. Relative to formalin-fixed and paraffin-embedded tissues, we compared the grading, staging, and interobserver variability. FS assessment demonstrated a sensitivity of 0.91 (95% CI, 0.77-0.97) and a specificity of 0.60 (95% CI, 0.36-0.80) for the presence of chorioamnionitis and a sensitivity of 0.89 (95% CI, 0.75-0.96) and a specificity of 0.69 (95% CI, 0.42-0.87) for the presence of funisitis. The χ2 goodness of fit for grade and stage in both placental membrane and umbilical cord sections was significant (P<.001). There was no significant difference in interobserver variability in comparison with permanent section results (P=0.06). We conclude that FS is a reasonably sensitive screening technique, correlating well with conventional assessment, without significantly different interobserver variability.