Does neuroprotective magnesium sulfate treatment impact short-term outcomes in preterm infants?

Abstract Objective: Magnesium sulfate (MgSO4) treatment is widely used for the fetal neuro-protective purpose along with the controversy concerning side effects. A scant number of studies searched the impact of different cumulative maternal doses and neonatal serum Mg levels on short-term neonatal morbidity and mortality. We opted to carry out a study to determine the impact of neonatal serum Mg levels on immediate neonatal outcomes. Study design: This prospective observational study was conducted between 2017 and 2021. Antenatal MgSO4 was used for the neuro-protective purpose only during the study period. Inborn preterm infants delivered between 23 and 32 weeks of gestation were enrolled consecutively. Routine neonatal serum Mg sampling was performed at the 6th hour of life. A neonatal Mg concentration of 2.5 mg/dl was used to classify MgSO4 exposed patients into two groups. Another analysis was performed between babies whose mothers were exposed to MgSO4 and those without. Finally, the groups were compared regarding neonatal outcomes. Result: Of the 584 babies, 310 received antenatal MgSO4. The birth weight was significantly lower in the MgSO4 exposed group (1113±361g vs. 1202±388g) (p=0.005). Antenatal corticosteroid usage and intrauterine growth restriction were also noted to be higher. MgSO4 group was more likely to have bronchopulmonary dysplasia, longer duration of invasive ventilation, necrotizing enterocolitis, patent ductus arteriosus, delayed full enteral nutrition, and feeding intolerance (p<0.05). MgSO4 treatment was found to be an independent risk factor for feeding intolerance (OR 2.09 95% CI 1.2-3.6, p=0.008). Furthermore Serum Mg level was significantly correlated with feeding intolerance (r =0.21, p=0.002). Conclusion: This study highlighted the effect of MgSO4 treatment and the the potential superiority of serum Mg level as a predictor of immediate neonatal outcomes, particularly delayed full enteral nutrition and feeding intolerance. Further studies are warranted to ascertain the optimal serum Mg concentration of preterm infants in early life that provides maximum benefit with minimal side effects.