Timing of administration of antenatal magnesium sulfate and umbilical cord blood magnesium levels in preterm babies

AbstractBackground: The optimum timing of administration of magnesium sulfate (MgSO4) in relation to delivery is not known. The general consensus is to achieve administration to the mother at least 4 hours prior to preterm delivery.Objective: To investigate potential predictors of umbilical cord blood magnesium (Mg) concentrations, in particular, timing of antenatal MgSO4 administration in relation to delivery.Study design: A prospective observational study of infants delivered at less than 32 weeks’ gestational age. Cord bloods samples were collected at delivery and Mg levels analyzed.Results: Of the 81 included cases, five received no antenatal MgSO4, 65 received a 4 g bolus only, and 11 received a 4 g bolus and 1 g/hour infusion. The median time of bolus administration before delivery was 104 minutes (IQR: 57–215). The mean magnesium level was 0.934 mmol/L in the no antenatal MgSO4 group, 1.018 mmol/L in the bolus only group, and 1.225 mmol/L in the bolus and infusion group (p < .05). In the bolus only...