Placentas were submitted for examination based on clinical
indications following national guidelines. All placental examinations
were performed in the Division of Perinatal Pathology,
Department of Pathology and Laboratory Medicine at the Women
and Infants’ Hospital of Rhode Island following a standard protocol. Placental pathology reports were generated by one of five board certified pediatric pathologists. Ten percent of all placental slides were audited and reviewed weekly. If there is disagreement
between the two pathologists, additional pathologists would
review the slides to help reach a consensus. This audit ensures that
the reports generated vary minimally among individual pathologists.
For the current study, gross placental parameters and
histopathology were extracted from the pathology report. Placental
weight is the trimmed weight of the placenta after removing the
membranes. Small for gestational age (SGA) is defined as weight
90th percentile. Fetal to
placental (F/p) weight ratio is often used as a marker for placental
efficiency. F/p ratio less than 10th percentile is usually suggestive
of placental insufficiency. Pathology seen in multi-gestational
pregnancy is counted once per side (or disk).
Histopathological diagnosis was classified into four groups
based on the presence of markers of maternal circulatory disorders,
fetal vascular obstruction, infection/inflammation and others.