Abstract / Summary
Abstract Objective： To investigate the effects of different doses of antenatal magnesium sulfate exposure on short-term outcomes of preterm infants < 32 weeks gestation and to analyze the differences in its effects across gestational age subgroups. Methods ：Preterm infants < 32 weeks gestation born at the Affiliated Zhangzhou Hospital of Fujian University between June 2023 and December 2025 were retrospectively enrolled. Infants were divided into low-dose group (≤30 g), high-dose group (>30 g), and non-exposure group based on cumulative antenatal magnesium sulfate dosage. Multivariable logistic regression was used to identify risk factors for death within 1 week after birth. Subgroup analyses were performed by gestational age (<28 weeks and 28–31⁺⁶ weeks) to compare the differences in primary outcomes (death within 1 week, grade III–IV intracranial hemorrhage(IVH)) and secondary outcomes (bronchopulmonary dysplasia(BPD), hemodynamically significant patent ductus arteriosus(hs PDA), necrotizing enterocolitis(NEC), retinopathy of prematurity(ROP), etc.) between the magnesium sulfate exposure group and the non-exposure group. Results： A total of 451 preterm infants were enrolled, including 143 (31.7%) in the low-dose group, 21 (4.7%) in the high-dose group, and 287 (63.6%) in the non-exposure group. Multivariable logistic regression showed that antenatal magnesium sulfate exposure was an independent protective factor for death within 1 week after birth (OR=0.197, 95%CI: 0.051–0.759, P=0.018). Gestational age subgroup analysis revealed that in the <28 weeks subgroup, the mortality rate within 1 week in the magnesium sulfate exposure group was significantly lower than that in the non-exposure group [5.1% (2/39) vs. 24.0% (18/75), P=0.024], while the incidence of grade III–IV IVH showed no significant difference between the two groups (P=0.931). In the 28–31⁺⁶ weeks subgroup, there were no significant differences between the two groups in mortality within 1 week (0.8% vs. 2.4%, P=0.509) or grade III–IV IVH (0% vs. 2.4%, P=0.194). Regarding complications, in the 28–31⁺⁶ weeks subgroup, the incidence of hsPDA at 2 weeks in the magnesium sulfate exposure group was significantly lower than that in the non-exposure group (3.9% vs. 12.0%, P=0.013), while the incidence of ROP was significantly higher (20.6% vs. 8.7%, P<0.001). In the <28 weeks subgroup, no significant differences were observed in any complication between the two groups (P>0.05). Conclusions： Antenatal magnesium sulfate exposure significantly reduces the risk of death within 1 week in preterm infants < 32 weeks gestation, and this protective effect is mainly concentrated in extremely preterm infants < 28 weeks.