Small Estimated Placental Volume Predicts Low Birthweight

The objective of the study was to validate Estimated Placental Volume (EPV) in a population of patients at Yale-New Haven Hospital (YNHH) across a range of gestational ages, and to evaluate the association between small EPV and low birthweight (BW). From 2009 to 2011, 366 patients at YNHH received ultrasound scans between 11+0 to 38+6 weeks gestational age (GA) to measure placental dimensions from 2009 to 2011. EPVs were calculated using a previously validated convex-concave shell equation. An EPV vs GA best fit curve was generated. The relationship between EPV and BW was analyzed. Subgroup analyses were performed to evaluate differences between study participants who delivered at YNHH, and those who did not. Analysis of EPV versus gestational age revealed a parabolic curve with the following best fit equation: EPV = (0.372 GA – 0.00364GA2)3. One hundred seventy four of the 366 women who underwent EPV measurement delivered at Yale-New Haven Hospital (YNHH) and had their infants’ BWs recorded. The remaining patients delivered at outlying hospitals, where BWs were not available to the investigators. However, parabolic EPV GA curves generated from these two patient populations were superimposable. YNHH 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% CI 1.27 – 4.68). Microscopic evaluation of two placentas corresponding to the smallest EPV outliers revealed significant placental pathology. We conclude that placental volume increases throughout gestation and follows a predictable parabolic curve. Very low EPV measurements are associated with low BWs. Therefore, EPV may be useful as a screen to identify women who are carrying fetuses who are at risk for intrauterine growth restriction