LAUSR

Abstract Objective  This study aimed to evaluate term neonatal outcomes after maternal magnesium sulfate (MgSO 4 ) treatment for seizure prophylaxis. Study Design  This was a single-site retrospective cohort study of all women with term singleton gestation requiring MgSO 4 treatment for seizure prophylaxis and their respective neonatal outcomes from January 2013 through December 2020. Our primary outcome was neonatal intensive care unit (NICU) admission. We compared outcomes between women treated with MgSO 4 for 24 hours or more and women treated with MgSO 4 for less than 24 hours prior to delivery. Multivariable logistic regression was performed to calculate adjusted odds ratio (aOR) and 95% confidence interval (95% CI), controlling for variables with a p  < 0.05 based on bivariable analysis. Results  Of 834 women analyzed, 173 (20.7%) neonates were admitted to the NICU. Women treated with MgSO 4 for 24 hours or more compared with women treated with MgSO 4 for less than 24 hours were more likely to have neonates admitted to the NICU during their hospitalization (27.3 vs. 18.9%; p  = 0.01), neonates requiring immediate NICU admission (24.6 vs. 18.3%; p  < 0.01), and NICU admission for neonatal lethargy. After adjusting for covariates, only NICU admission due to neonatal lethargy remained statistically significant (aOR: 4.78 [95% CI: 1.50–15.21]). Conclusion  Prolonged MgSO 4 treatment for 24 hours or more was associated with increased odds of term NICU admission due to neonatal lethargy. Key Points NICU admission rose with longer magnesium treatment. Nulliparous patients had more magnesium sulfate exposure. Obese patients had longer magnesium sulfate exposure.