Determination of Placental Weight Using Two-dimensional Sonography and Volumetric Mathematic Modeling

An abnormally decreased placental weight has been linked to increased perinatal complications, including intrauterine fetal demise (IUFD) and fetal growth restriction (IUGR). Despite its promise, determining placental weight prenatally using three-dimensional systems is time-consuming and requires expensive technology and expertise. We propose a novel method using two-dimensional sonography that provides an immediate estimation of placental volume. Placental volume was calculated in 29 third-trimester pregnancies using linear measurements of placental width, height, and thickness to calculate the convex-concave shell volume within 24 hours of birth. Data were analyzed to calculate Spearman's rho (r(s)) and significance. There was a significant correlation between estimated placental volume (EPV) and actual placental weight (r(s) = 0.80, p<0.001). Subgroup analysis of preterm gestations (n = 14) revealed an even more significant correlation of EPV to actual placental weight (r(s) = 0.89, p<0.001). Placental weight can be accurately predicted by two-dimensional ultrasound with volumetric calculations. This method is simple, rapid, and accurate, making it practical for routine prenatal care, as well as for high-risk cases with decreased fetal movement and IUGR. Routine EPV surveillance may decrease the rates of perinatal complications and unexpected IUFD.