Placental Calcification Score: a new semiquantitative method to assess pattern and grading of placental calcifications

The relationship between placental calcifications and pregnancy outcome is still controversial. In this study, we examined the occurrence of placental calcifications, and we proposed a histopathological score system, Placental Calcification Score (PCS). We assigned a score (from 1 to 3) to calcifications according to their pattern (dusty = 1; single = 2; cluster = 3) and grading (low = 1; moderate = 2; high = 3). Multiplying the pattern score with that of grading, we obtained a score. After that, summing the score of each one of the three calcification patterns, we achieved the PCS. We examined 47 consecutive monochorionic placentas, searching calcifications in placental parenchyma (PP) (in which we distinguished four subsites: intervillous, intravillous, sub-amniotic fetal floor and decidua), extraplacental membranes and Wharton jelly of the umbilical cord. We collected clinical data relative to 47 mothers (age, gestational age at delivery, kind of gestation and hypertension) and 51 products of conception (kind of products of conception, gender, preterm birth, and intrauterine growth restriction [IUGR]), corresponding to the 47 placentas. We found calcifications in all placentas examined (47/47 = 100%), and all placentas showed calcifications in PP (47/47 = 100%). Calcifications were more frequent, respectively, in intravillous (36/47 = 77%) and intervillous (47/47 = 100%) subsite of PP. Besides, our preliminary data showed a mean PCS higher in mothers ≥ 35 years, with gestational age ≥ 37 W + 0 D and suffering from hypertension, than in mothers < 35 years, with gestational age < 37 W + 0 D and without hypertension. Not preterm newborns, male gender, and presence of IUGR were associated with a mean PCS higher than preterm newborns, female gender, and absence of IUGR. PCS is a new histopathological tool that might be useful to clarify the correlation between placental calcifications and clinical data of mothers and products of conception. Further investigations are needed, with a large number of placentas, to confirm the trend shown by our data.