Reducing Adverse Effects of Antenatal Magnesium Therapy for Neuroprotection: Tailoring Treatment to the Intended Recipient

Abstract

Magnesium sulfate is widely administered to pregnant women at risk of preterm delivery for neuroprotection. However, there are no uniform guidelines in the dosing protocol for magnesium use. While antenatal magnesium therapy reduces the risk of cerebral palsy and gross motor dysfunction, adverse neonatal outcomes related to magnesium have been reported by some, and are the subject of considerable debate. There may be a therapeutic window within which the neuroprotective effects of magnesium sulfate are observed, with adverse neonatal outcomes at levels outside this window. Magnesium sulfate is one of few drugs currently administered in a “one dose fits all” regimen, without taking into account maternal or fetal parameters. While the mother is monitored and her dose is adjusted as needed, the fetus is not monitored (neither in utero nor in the NICU). Inability to monitor the fetal magnesium concentration while in utero may be countered by identifying variables that influence fetal serum magnesium levels and attempting to adjust the maternal dose accordingly. Further studies with larger sample sizes are needed to determine the optimal dose of maternal magnesium to provide fetal neuroprotection or maternal seizure prophylaxis with minimal neonatal adverse outcomes. It may be possible that monitoring neonatal serum magnesium concentrations and treating neonates with high levels may impact their outcomes and this is an option that needs to be explored.