Antenatal magnesium sulfate treatment and risk of necrotizing enterocolitis in preterm infants born at less than 32 weeks of gestation

Antenatal magnesium sulfate (MgSO(4)) treatment is widely used for fetal neuroprotection in women at risk of preterm delivery. However, some studies have recently suggested that in utero MgSO(4) exposure is associated with an increased risk of necrotizing enterocolitis (NEC). This study aimed to investigate the association between antenatal MgSO(4) treatment and risk of NEC. This retrospective cohort study included 756 infants born at 24‒31 weeks’ gestation. Subjects were classified into three groups: period 1, when MgSO(4) treatment protocol for fetal neuroprotection was not adopted (n = 267); period 2, when the protocol was adopted (n = 261); and period 3, when the protocol was withdrawn because of concern of risk of NEC (n = 228). Rates of NEC (≥ stage 2b) were analyzed according to time period and exposure to antenatal MgSO(4). Significant difference in the rate of NEC was not found across the three time periods (2.6% vs. 6.5% vs. 4.8% in periods 1, 2 and 3, respectively, p = 0.103). The rate of NEC was comparable between the infants exposed and unexposed to antenatal MgSO(4) (5.1% vs. 3.6%, p = 0.369). These results showed that antenatal MgSO(4) treatment was not associated with risk of NEC in our study population.