Electro-clinical efficacy and safety of midazolam in neonatal seizures: a systematic review with individual level exploratory analysis of gestational age-related treatment response.
UNLABELLED: Neonatal seizures are the most common neurological emergency during the neonatal period and are associated with increased mortality and adverse neurodevelopmental outcomes. Despite current recommendations supporting phenobarbital as first-line therapy, seizure control remains suboptimal in a large proportion of neonates, prompting the use of second-line antiseizure medications. Midazolam is increasingly administered in refractory neonatal seizures but evidence regarding its electro-clinical efficacy and safety remains limited and heterogeneous. To systematically review the available evidence on the electro-clinical efficacy and safety of midazolam in neonatal seizures and to perform an exploratory individual-level analysis investigating the association between gestational age and treatment response. A systematic review was conducted according to PRISMA 2020 guidelines. Studies including neonates with EEG- or aEEG-confirmed seizures treated with midazolam were included. Binary logistic regression was performed to assess the individual-level association between gestational age and treatment response. Eleven studies involving 146 neonates treated with midazolam were included. Electro-clinical response was observed in 101/146 neonates (69.2%), while seizure cessation was achieved in 61/146 neonates (41.8%). In an exploratory complete-case logistic regression analysis, higher gestational age appeared to be associated with a greater probability of electro-clinical response. The predicted probability curve crossed the 50% response probability at approximately 36.5 weeks of gestation. Hypotension was the most frequently reported adverse event, while respiratory depression, sedation-related effects, and transient EEG/aEEG suppression were reported less frequently. CONCLUSIONS: Midazolam may have a role as an add-on antiseizure medication in neonatal seizures, particularly in refractory cases. However, the evidence remains limited by heterogeneity in study design, EEG monitoring strategies, outcome definitions, and incomplete individual-level data. The observed association between gestational age and response is hypothesis-generating and requires prospective validation. WHAT IS KNOWN: • Phenobarbital often provides incomplete seizure control in neonates, making second-line antiseizure therapies necessary in refractory cases. • Evidence supporting midazolam for neonatal seizures remains limited and heterogeneous. WHAT IS NEW: • This systematic review summarizes the electro-clinical efficacy and safety of midazolam and includes an exploratory patient-level analysis suggesting that higher gestational age may be associated with improved treatment response. • These findings support further prospective studies on developmental determinants of response to GABAergic therapy.