Lack of Evidence for Time or Dose Relationship between Antenatal Magnesium Sulfate and Intestinal Injury in Extremely Preterm Neonates

Abstract

Background: Recent studies reported conflicting results on the relationship between antenatal magnesium sulfate (MgSO₄) exposure and neonatal intestinal injury. Most studies have not assessed MgSO₄ exposure quantitatively and none reported the exposure timing. Objectives: The aim of this work was to assess whether there is a temporal or dose-dependent relationship between antenatal MgSO₄ exposure and intestinal injury in extremely preterm neonates. Methods: A retrospective study was made of inborn neonates with gestational age ≤28 weeks and/or birth weights ≤1,000 g. Primary outcomes included necrotizing enterocolitis (NEC), spontaneous intestinal perforation (SIP), and/or death prior to discharge or in the first 2 weeks of life. Outcome comparisons were made based on the timing of MgSO₄ exposure, within 7 days (Mg7D) or within 3 days (Mg3D) of birth. Total cumulative doses for the Mg3D group were also computed. Results: A total of 302 neonates were included, 210 in the Mg7D group, out of whom 179 (85.2%) constituted the Mg3D group. There were no differences noted when comparing MgSO₄ exposure timing and the likelihood of NEC, SIP, and/or death. This remained the same for subgroup analysis of neonates < 26 weeks’ gestation. Each 10-g increase in MgSO₄ cumulative dose correlated with a decrease in SIP/NEC/death by 18.9% prior to discharge and by 21.9% in the first 2 weeks of life. Small for gestational age (SGA) was a potential effect modifier by a likelihood ratio test with p = 0.07. Conclusions: Antenatal MgSO₄ exposure in extremely preterm neonates was not associated with an increased risk of intestinal injury or death, and might have reduced these complications in a dose-dependent manner in our study. This protective effect was more noticeable in SGA neonates.