Objective: To confirm the role of fetal growth restriction (FGR) as a cause of stillbirth, and to compare diagnostic accuracy of customized fetal growth and population-based standards in identifying FGR within a pathological population of early and late stillbirths.
Methods: Retrospective study on a cohort of 189 stillbirths occurred in single pregnancy between January 2006 and September 2011. Unexplained stillbirths, defined by Aberdeen-Wigglesworth and ReCoDe classifications, were evaluated on the basis of fetal birthweight with both Tuscany population and Gardosi customized standards. Unexplained stillbirths have been classified as early or late depending on the gestational age of occurrence.
Results: Aberdeen-Wigglesworth classification, applied to the 189 cases of stillbirth, left 94 unexplained cases (49.7%), whereas the ReCoDe classification left only 40 (21%). By applying population standards to the 94 unexplained stillbirths we have identified 31 FGRs (33% of sample), while customized standards identified 54 FGRs (57%). Customised standards identified a larger number of FGRs with respect to population standards during the third trimester (i.e. 51% vs. 25% respectively) than in the second trimester (73% vs. 54% respectively) (p = 0.05).
Conclusions: Customized standards have a higher diagnostic accuracy in identifying FGRs especially during the third trimester.