Background and aims Neonatal hypoxic-ischaemic encephalopathy (HIE) can lead to neurodevelopmental impairment, raising a need for early prognostic tools to guide therapy. The prognostic value of HMRS performed between 5–30 days of life has been extensively studied, although few studies focus on earlier periods. Therefore, we investigated the prognostic performance of HMRS during the first 96 h of life.

Methods 55 consecutive hypothermia-treated HIE neonates were examined by HMRS at three echo-times (TE = 35 ms, 144 ms, 288 ms) between 6–96 h of age, depending of clinical stability. Patients were divided into favourable (n = 38) and unfavourable (n = 17) outcome groups based on Bayley II MDI and PDI scores (≥70 vs <70 or death, respectively) assessed at 18–26 months of age. Associations between 36 routinely measured metabolite ratios (MROs) and outcome were studied. The prognostic performance of MROs was evaluated by ROC analysis. Time-dependent changes of MROs in whole patient population were also assessed.

Results 6 MROs showed significant difference between outcome groups after correction for multiple testing (p < 0.0014). ROC analysis revealed that Myo-inositol/N-Acetyl-Aspartate (TE = 35) gives best prediction for outcome with 85.71% sensitivity and 91.30% specificity. Assessment of time-dependency showed that 4 of 6 MROs stay constant during the first 96 h of life, all containing Myo-inositol.

Conclusions Our findings suggest that during the first 96 h of life HMRS could be a useful early prognostic tool in predicting the outcome of asphyxiated neonates. Myo-inositol/N-Acetyl-Aspartate ratio was found to be the best and time-independent predictor.