Abstract
In the management of pregnancy, ritodrine has been used to prevent preterm birth, and magnesium sulfate (MgSO4) has been used to prevent preterm labor and preeclampsia. Neonates born to mothers receiving these medications occasionally show an increase in serum potassium concentration. Recently, an elevated risk of neonatal hyperkalemia has been reported, particularly when ritodrine and MgSO4 are co-administered; however, the underlying mechanisms remain unclear. We investigated the association between potassium levels and metabolites in the serum of umbilical cord blood of infants with antenatal exposure to antenatal ritodrine and MgSO4 using a metabolomic analysis. Our findings revealed a significant elevation in serum potassium concentration associated with metabolomic findings of activation of glycolysis and the derived metabolic routes in preterm neonates exposed to both ritodrine and MgSO4. Our data indicate that the concurrent administration of ritodrine and MgSO4 caused distinctive metabolic alterations, potentially leading to an additional increase in the intracellular potassium concentration in the fetus. Consequently, this mechanism may imply an elevation in serum potassium concentration postnatally through the redistribution of potassium.