Systematic review on first trimester three-dimensional placental volumetry predicting small for gestational age infants

Objective: A systematic review and pooled analysis was carried out to estimate (i) the reference values and (ii) the potential value of measuring the first-trimester 3D-placental volume (PV) for predicting small for gestational age (SGA) infants. Method: A comprehensive literature search for relevant studies was conducted using the PubMed and Web of Knowledge databases. A simulation model was generated to calculate the detection rate (DR) of the PV for SGA infants. A random variable was generated having the same number of cases, and the same means and standard deviation as those reported in the articles considered for the analysis. Results: For the evaluation of the normal values of PV, 12 studies met the inclusion criteria. Four also produced an equation for PV estimation at 11 to 14weeks. The weighted mean PV [±standard error of mean (SEM)] of 7519 cases was 59.40±1.533mL. For the estimation of PV performance in predicting SGA, five studies were included. The DR of the PV was 24.7% (19.3-30.1) at a 10% false-positive rate. Conclusion: The mean PV estimation of the studies analyzed was burdened by a high degree of heterogeneity. Instead, discordant results were reported for the possible prediction of SGA infants using PV. Surprisingly, just two articles reported the DR for SGA infants and also had proper statistical power. The discriminatory ability of using PV alone for predicting SGA appears to be modest, but could successfully be integrated into a multivariable screening method for SGA infants.