Consensus Definition of Fetal Growth Restriction in Intrauterine Fetal Death: A Delphi Procedure

Abstract

Context.— Fetal growth restriction is a risk factor for intrauterine fetal death. Currently, definitions of fetal growth restriction in stillborns are heterogeneous. Objectives.— To develop a consensus definition for fetal growth restriction retrospectively diagnosed at fetal autopsy in intrauterine fetal death. Design.— A modified online Delphi survey in an international panel of experts in perinatal pathology, with feedback at group level and exclusion of nonresponders. The survey scoped all possible variables with an open question. Variables suggested by 2 or more experts were scored on a 5-point Likert scale. In subsequent rounds, inclusion of variables and thresholds were determined with a 70% level of agreement. In the final rounds, participants selected the consensus algorithm. Results.— Fifty-two experts participated in the first round; 88% (46 of 52) completed all rounds. The consensus definition included antenatal clinical diagnosis of fetal growth restriction OR a birth weight lower than third percentile OR at least 5 of 10 contributory variables (risk factors in the clinical antenatal history: birth weight lower than 10th percentile, body weight at time of autopsy lower than 10th percentile, brain weight lower than 10th percentile, foot length lower than 10th percentile, liver weight lower than 10th percentile, placental weight lower than 10th percentile, brain weight to liver weight ratio higher than 4, placental weight to birth weight ratio higher than 90th percentile, histologic or gross features of placental insufficiency/malperfusion). There was no consensus on some aspects, including how to correct for interval between fetal death and delivery. Conclusions.— A consensus-based definition of fetal growth restriction in fetal death was determined with utility to improve management and outcomes of subsequent pregnancies.