Prediction of adverse neonatal outcome is improved using the Delphi consensus definition for FGR

The current definition of FGR is based on an estimated weight (EFW) < 10th percentile, ultrasound abdominal circumference (AC) < 10th, or deflection of growth of at least 20 percentiles. Recently, a new international consensus definition of FGR has been proposed using a Delphi procedure. It is not yet clear which definition has a better predictive value for adverse perinatal outcome in FGR fetuses. We aimed to evaluate whether the Delphi consensus definition has a stronger association with adverse perinatal outcome compared to the current definition of FGR. A retrospective cohort study of singleton pregnancies presenting for a routine check-up or an ultrasound scan between 18 and 38 weeks of gestation at the Maastricht University Medical Centre was performed. The current definition of FGR was compared to the Delphi consensus definition in terms of sensitivity, specificity and predictive value. Primary outcome was a composite of severe adverse perinatal outcome. Secondary outcomes were a composite of mild adverse perinatal outcome. Although the prediction of SGA neonates was similar for the Delphi consensus and current definitions for FGR, the sensitivity of the Delphi definition for diagnosing severe adverse perinatal outcome was higher (37,4 vs. 18,8%), respectively. Of the 1477 pregnancies included, 426 had severe adverse perinatal outcome (28,8%), of which 45,8% in the Delphi consensus group and 26,3% in the group of the current definition, with an odds ratio (OR) of 2,36 (95% confidence interval (CI) 1,64-3,38) for the Delphi definition. Mild adverse perinatal outcome was also more common in the Delphi definition group compared to the current definition group (55,8% vs. 32,9%; OR 2,57 (95% CI, 1,81-3,62)). Positive and negative predictive value for adverse perinatal outcome were 45.8% and 76.3% for the Delphi definition and 33.5% and 72.1% for the current definition. The FGR Delphi consensus definition has a stronger association and accuracy with adverse perinatal outcome compared to the current FGR definition.