Estimated Placental Volume and Gestational Age.

Objective The objective of this study was to validate estimated placental volume (EPV) across a range of gestational ages (GAs). Study Design Three hundred sixty-six patients from 2009 to 2011 received ultrasound scans between 11+0 and 38+6 weeks GA to assess EPV. An EPV versus GA best fit curve was generated and compared with published normative curves of EPV versus GA in a different population. A subanalysis was performed to explore the relationship between EPV and birth weight (BW). Results Analysis of EPV versus GA revealed a parabolic curve with the following best fit equation: EPV=(0.372 GA-0.00364 GA (2) ) (3) . EPV was weakly correlated with BW, and patients with an EPV in the bottom 50th percentile had 2.42 times the odds of having a newborn with a BW in the bottom 50th percentile (95% confidence interval: 1.27-4.68). Microscopic evaluation of two placentas corresponding to the smallest EPV outliers revealed significant placental pathology. Conclusion Placental volume increases throughout gestation and follows a predictable parabolic curve, in agreement with the existing literature. Further validation is required, but EPV may have the potential for clinical utility as a screening tool in a variety of settings.