Consensus definition and essential reporting parameters of selective fetal growth restriction in twin pregnancy: a...

Twin pregnancy complicated by selective fetal growth restriction (sFGR) is associated with increased perinatal mortality and morbidity. Inconsistencies in the diagnostic criteria for sFGR employed in existing studies hinder the ability to compare or combine their findings. It is therefore challenging to establish robust evidence-based management or monitoring pathways for these pregnancies. The main aim of this study was to determine, by expert consensus using a Delphi procedure, the key diagnostic features of and the essential reporting parameters in sFGR.

A Delphi process was conducted among an international panel of experts in sFGR in twin pregnancy. Panel members were provided with a list of literature-based parameters for diagnosing sFGR and were asked to rate their importance on a five-point Likert scale. Parameters were described as solitary (sufficient to diagnose sFGR, even if all other parameters are normal) or contributory (those that require other abnormal parameter(s) to be present for the diagnosis of sFGR). Consensus was sought to determine the cut-off values for accepted parameters, as well as parameters used in the monitoring, management and assessment of outcome of twin pregnancy complicated by sFGR. The questions were presented in two separate categories according to chorionicity.

A total of 72 experts were approached, of whom 60 agreed to participate and entered the first round; 48 (80%) completed all four rounds. For the definition of sFGR irrespective of chorionicity, one solitary parameter (estimated fetal weight (EFW) of one twin < 3^rd centile) was agreed. For monochorionic twin pregnancy, at least two out of four contributory parameters (EFW of one twin < 10^th centile, abdominal circumference of one twin < 10^th centile, EFW discordance of ≥ 25%, and umbilical artery pulsatility index of the smaller twin > 95^th centile) were agreed. For sFGR in dichorionic twin pregnancy, at least two out of three contributory parameters (EFW of one twin < 10^th centile, EFW discordance of ≥ 25%, and umbilical artery pulsatility index of the smaller twin > 95^th centile) were agreed.

Consensus-based diagnostic features of sFGR in both monochorionic and dichorionic twin pregnancies, as well as cut-off values for the parameters involved, were agreed upon by a panel of experts. Future studies are needed to validate these diagnostic features before they can be used in clinical trials of interventions. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.