Delayed Prenatal Development of the Insula Lobe in SGA Fetuses at 2D Ultrasonography: A Perspective-Changing Retrospective Study

Introduction: delayed fetal cortical development is associated with the risk of future neurological and/or psychomotor issues.However, the process of prenatal brain folding in small for gestational age (SGA) fetuses remains understudied.In this study we evaluated by two-dimensional ultrasound (2D-US) whether there is a difference in the development of the Insula Lobe (IL), the Sylvian Fissure (SF) and/or the SF-ratio between appropriate-for-gestational-age (AGA) and SGA fetuses.Methods: a retrospective study was conducted by measuring the IL, SF and SF ratio in 137 SGA-births between 20 and 36 weeks of gestational age (GA), with and without Doppler abnormalities and comparing it to published reference values for AGA cases.Results: a significant different development of the IL (p = 0.025) was observed for SGA compared with AGA-fetuses.No statistically significant differences were found comparing subgroups without (constitutional SGA) or with Doppler abnormalities (pathological SGA).Conclusion: we found a delayed development of the IL in SGA, independently on its constitutional or pathological origin, in comparison with AGA-fetuses at prenatal 2D-US.Further studies, assessing also later cognitive and psychomotor development, are encouraged to address this issue.