Brain metabolism in fetal intrauterine growth restriction: a proton magnetic resonance spectroscopy study

OBJECTIVE: The purpose of this study was to investigate alterations in brain metabolism in fetuses with intrauterine growth restriction (IUGR) and evidence of cerebral redistribution of blood flow. STUDY DESIGN: Biometry and Doppler assessment of blood flow was assessed with ultrasound in 28 fetuses with IUGR and cerebral redistribution and in 41 appropriately grown control subjects. Proton magnetic resonance spectroscopy of the fetal brain was then performed to determine the presence of choline (Cho), creatine (Cr), N-acetylaspartate (NAA), and lactate and to generate ratios for NAA: Cho, NAA: Cr, and Cho: Cr. RESULTS: Sixty-five percent of spectra were interpretable: N-acetylaspartate, choline, and creatine peaks were identified in all these spectra; lactate was present in 5 IUGR fetuses and in 3 appropriately grown fetuses. NAA:Cr and NAA:Cho ratios were significantly lower in IUGR fetuses with cerebral redistribution. CONCLUSION: Cerebral redistribution is associated with altered brain metabolism that is evidenced by a reduction in NAA:Cho and NAA:Cr ratios.