Third trimester growth restriction patterns: individualized assessment using a fetal growth pathology score

Abstract

Objective: To qualitatively and quantitatively characterize third trimester growth patterns in fetuses/neonates with growth restriction using Individualized Growth Assessment.

Methods: Serial fetal size measurements from 73 fetuses with proven growth restriction were evaluated using a novel composite parameter, the Fetal Growth Pathology Score (FGPS1). Third trimester FGPS1 measurements plotted against fetal age were examined for patterns. Identified patterns were characterized using the four components of the FGP1 [head circumference (HC), abdominal circumference (AC), femur diaphysis length (FDL), estimated weight (EWT)]. A secondary characterization using age of onset, duration and magnitude of the growth abnormality process was also performed. Frequencies and magnitudes of abnormal values in different FGPS1 patterns were compared.

Results: Five growth restriction patterns were found in 70/73 (95.9%) of the cases, with progressive worsening [Pattern 1 (37.0%)] and abnormal growth identified only at last scan [Pattern 2 (27.4%)] being the most common. These two patterns were usually statistically different from each other and the other three with respect to size parameter abnormalities and abnormal growth process characteristics (MANOVA). Growth abnormalities in all parameters of the FGPS1 contributed to the five abnormality patterns although AC and EWT were most important. The age of onset, duration and magnitude were similar between patterns except for Pattern 2, which had a late onset and a short duration (GLM + contrasts).

Conclusions: Our study represents the first detailed evaluation of third trimester growth restriction using methods that consider the growth potential of each fetus. Five distinctive and repetitive patterns were found, suggesting that fetal growth restriction evolves in different ways. Further research is needed to determine the relationships of these patterns to physiological/biochemical changes and adverse outcomes associated with growth restriction.

Keywords:

• Individualized growth assessment
• longitudinal growth study
• SGA

Disclosure statement

Authors thank Rose Torno, Chair at Mount Sinai Hospital, University of Toronto, and John Kingdom. This research was supported (in part) by the Perinatology Research Branch, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, DHHS. R. Romero contributed to this work as part of his official duties as an employee of the USA Federal Government. None of the other authors have disclosed a conflict of interest.