Timing of administration of antenatal magnesium sulphate and correlation with umbilical cord blood magnesium levels in preterm babies.

BACKGROUND: The effectiveness of MgSO4 for foetal neuroprotection is acknowledged, but the best time to provide it in relation to birth is a conundrum, and dose schedule is yet unknown. Understanding the determinants of the magnesium levels in cord blood aids in determining the appropriate timing and length of administration.

AIM AND OBJECTIVE: To assess the cord blood magnesium concentration in relation to the timing of MgSO4 and delivery. To achieve ROC in relation to optimum level of cord blood magnesium concentration in relation to neonatal outcome variables.

STUDY DESIGN: A prospective observational study conducted in a tertiary care hospital over 2 years in women having preterm delivery from 26 weeks to 33 + 6 weeks, who received Neuroprophylaxis. Cord blood was collected for magnesium level estimation. Baby followed 24 h after delivery. ROC analysis performed for predicting an optimal cut-off for a continuous predictor predicting binary outcome.

RESULTS: 85 recruited cases divided into bolus group, bolus + infusion group. The mean cord blood magnesium (n = 85) was 3.8 mg/dl. The AUROC for Gestational Age at Administration predicting Baby Outcome: 0.699, It was statistically significant (p = 0.034). The AUROC for Cord Blood Mg predicting Baby Outcome: 0.606, It was not statistically significant (p = 0.262).

CONCLUSION: Mean cord blood magnesium levels served as a tool to determine the timing and duration of Neuroprophylaxis. Mean cord blood magnesium of 3.8 mg/dl should be achieved to serve the purpose of Neuroprotection. To achieve this, Bolus followed by Infusion should be administered for at-least 6 h prior to delivery.