OC04.01: Late Onset Intrauterine Growth Restriction: from Prenatal Diagnosis to Short‐term Neurodevelopment Outcomes

We sought to investigate alterations in fetal growth and fetal brain growth in the setting of late-onset IUGR, and examine their relationship with placental function, fetal hemodynamics and neurodevelopmental outcomes. We performed an observational study in 98 fetuses enriched for low estimated fetal weight, using cine phase-contrast MRI and MR oximetry to assess blood flow and oxygen saturations. Pulsatility index (PI) and cerebroplacental ratio (CPR) were measured in the middle cerebral artery and umbilical artery (UA). Newborns underwent brain MRI during natural sleep, including diffusion tensor imaging, MR spectroscopy and total brain volume. The patients were followed up with the Bayley-III score at 18 months. Patients were divided into two groups comprising 42 late-onset IUGR fetuses and 56 normal controls based on a multiparametric IUGR scoring system. We found associations between body growth and umbilical vein (UV) flow (r=0.58, p < 0.0001) and oxygen saturation (r=0.22, p = 0.03). Measures of neonatal brain growth were associated with fetal ascending aortic oxygen saturation (r=0.39, p = 0.004). Growth restricted newborns had significantly smaller brains (p = 0.03) and lower fetal oxygen consumption (p = 0.003). MR diffusion tensor imaging revealed significantly reduced mean FA in the anterior, central, and posterior white matter of the brain in newborns with IUGR (p = 0.046) and reduced mean ADC in the anterior white matter (p = 0.0001). We observed an association between NAA-to-creatine ratio and neonatal brain volume (p = 0.03). Prenatal superior vena caval blood flow by MRI were inversely correlated to cognitive score and language score, while CPR and UA PI were associated with motor score. Our findings confirm that late onset IUGR newborns have impaired in utero brain growth which has a persistent impact on neurodevelopmental outcomes. The presence of brain sparing physiology predicted worse brain growth and subsequent development, and should be regarded as an indication for neurodevelopmental follow-up.