Isakov et al reported an equation for estimating the volume of a placenta based on gestational age, assuming normal development. The authors are from Yale University, Boston University and Icahn School of Medicine at Mount Sinai in New York.

Patient selection: 11 to 39 weeks of gestation


Analysis: ultrasonography



(1) gestational age in weeks


estimated placental volume in cubic cm =

= ((0.372 * (gestational age)) - (0.00364 * ((gestational age)^2)))^3


The volume can also be derived from the placental weight if the density is known (estimated at 1.05 per cubic cm).



• The weight based on estimated volume is significantly higher than that reported in reference tables.

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