Reliability of placental histology using archived specimens

Archived placental materials provide a resource for retrospective studies o f perinatal outcomes. Using archived specimens, we evaluated inter-rater re liability in the assessment of placental histological features possibly ass ociated with neonatal illness and long-term neurological outcome. Five expe rt placental pathologists independently reviewed archived placental specime ns on 30 subjects born during 1983-85 in six different hospitals. Moderate to substantial agreement among the raters was observed for a variety of ind icators of inflammation, presence of macrophages with pigment and indicator s of villous maturity, increased syncytial knots and maternal vasculopathy. , Existing pathology reports for these specimens from routine histology exa minations conducted at the time of delivery were in substantial agreement w ith expert review for the presence of any subchorionitis/chorionitis/chorio amnionitis. In conclusion, considerable inter-rater agreement was observed for several relatively common and potentially important placental findings. Archived placental materials and pathology reports may be useful in retros pective studies.