Novel Placental Functional Capacity Score: A Single Quantitative Score Estimating Placental Function and Its Association with Pregnancy Outcomes

BACKGROUND: Determining placental functional capacity from a typical pathology report can be difficult. Our goal was to create a new way to report on the functional capacity of the placenta, using much of the typical information obtained in a routine placental pathology assessment. METHODS: Placental functional capacity score (PFCS), a continuous variable between 0 and 100, was defined by a combination of placental weight compared to that expected for gestational age, villous maturational abnormalities, percentage of parenchymal lesions, and presence of inflammation. We compared PFCS distributions in 3 existing placental pathology repositories, 2 with livebirths (n = 9783 and n = 575) and 1 with stillbirths (n = 149). Within the 2 livebirth cohorts, we compared PFCS by adverse pregnancy outcomes. Data were analyzed using SPSS and RStudio. RESULTS: PFCS could be robustly applied in the 3 cohorts and could be calculated using simple formulas easily applied by software programs. Mean PFCS was 74.60 (SD 18.09) and 77.23 (SD 16.56) in the 2 liveborn cohorts, but was markedly reduced to 62.61 (SD 28.92) in the stillbirth cohort (p<.0001). Mean PFCS was significantly lower in preterm birth compared to term births, SGA infant versus non-SGA infant, and preeclampsia versus no preeclampsia, in both of the liveborn cohorts. CONCLUSION: It is feasible to calculate a continuous, quantitative PFCS from information collected in routine placental pathology examination, and PFCS is reduced in stillbirths compared to live birth, in preterm births compared to term births, and in SGA infants compared to non-SGA infants.