Antenatal magnesium exposure and neonatal demise

Objective: To assess the effect of antenatal magnesium sulfate exposure on neonatal demise. Study Design: A retrospective analysis of prospectively captured data from 100 tertiary centers between May 1997 and January 2000 was performed. Included were nonanomalous newborns who were admitted to the neonatal intensive care unit between 23 and 34 completed weeksʹ gestation. Predictors of neonatal demise were determined from a pool of 24 candidate variables in a univariate analysis. A multivariate predictive model for mortality was constructed by using the variables that had significant interactions with the rate of demise (P ≤.1). Results: A total of 12,876 cases were available for analysis. When these cases were stratified according to gestational age, magnesium was associated with a significant reduction in neonatal demise (OR, 0.67; 95% CI, 0.54 to 0.84; P = .0005). The effect remained when controlling for both gestational age and indication for therapy (adjusted OR, 0.70; 95% CI, 0.56 to 0.89; P = .003). The effect was similar in direction and magnitude in the final model after controlling for additional antenatal factors (OR, 0.82; 95% CI, 0.65 to 1.04;P: = .108). Conclusion: Antenatal magnesium exposure is not associated with neonatal death, regardless of indication for therapy. (Am J Obstet Gynecol 2001;185: 869-72.)