OBJECTIVE: To compare fetuses with intrauterine growth restriction (IUGR) and those with normal growth, in terms of skull and brain measurements obtained by magnetic resonance imaging (MRI). MATERIALS AND METHODS: This was a prospective cohort study including 26 single fetuses (13 with IUGR and 13 with normal growth), evaluated from 26 to 38 weeks of gestation. Using MRI, we measured skull and brain biparietal diameters (BPDs); skull and brain occipitofrontal diameters (OFDs); corpus callosum length and area; transverse cerebellar diameter; extracerebral cerebrospinal fluid (eCSF); and right and left interopercular distances (IODs). RESULTS: The following were significantly smaller in IUGR fetuses than in control fetuses: skull BPD (76.9 vs. 78.2 mm; p = 0.0029); brain BPD (67.8 vs. 71.6 mm; p = 0.0064); skull OFD (93.6 vs. 95 mm; p = 0.0010); eCSF (5.5 vs. 8.2 mm; p = 0.0003); right IOD (9.8 vs. 13.9 mm; p = 0.0023); and left IOD (11.8 vs. 16.3 mm; p = 0.0183). The skull BPD/eCSF, brain BPD/eCSF, skull OFD/eCSF, and brain OFD/eCSF ratios were also lower in IUGR fetuses. CONCLUSION: IUGR fetuses had smaller OFD and BPD, both skull and brain, and less eCSF when compared to normal growth fetuses.

Keywords: Fetus; Ultrasonography; Magnetic resonance imaging; Intrauterine growth restriction; Brain; Cerebrospinal fluid.