Increased Risk of Meconium-Related Ileus in Extremely Premature Infants Exposed to Antenatal Magnesium Sulfate

<b><i>Introduction:</i></b> We experienced an increased incidence of meconium-related ileus (MRI) in extremely premature infants (EPIs) while adopting the antenatal magnesium sulfate (MgSO₄) protocol for fetal neuroprotection in our neonatal intensive care unit. This study aimed to test whether antenatal MgSO₄ use was associated with increased risk of MRI in EPIs. <b><i>Methods:</i></b> The incidences of complicated MRI requiring aggressive enema or surgical intervention and other intestinal complications were compared among period 1 (January 2012–December 2013, <i>n</i> = 79), before adoption of the antenatal MgSO₄ protocol for fetal neuroprotection; period 2 (January 2014–March 2016, <i>n</i> = 72), when the protocol was adopted; and period 3 (April 2016–September 2018, <i>n</i> = 75), when the protocol was temporarily withdrawn due to concern regarding intestinal complications in EPIs. <b><i>Results:</i></b> Despite similar baseline clinical characteristics among infants across the study periods, the MRI and MRI with surgical treatment incidences were higher in period 2 than those in periods 1 and 3 (13% vs. 8% and 6%, <i>p</i> = 0.391, and 11% vs. 0% and 1%, <i>p</i> = 0.001, respectively). In multivariable analysis, exposure to antenatal MgSO₄ independently increased the risk of MRI (adjusted odds ratio, 3.8; 95% confidence interval, 1.4, 10.6). <b><i>Conclusion:</i></b> Antenatal MgSO₄ may increase the risk of MRI, frequently requiring surgical intervention, in EPIs with a gestational age of 25 weeks or less.

Neonatal Magnesemia in Preterm Neonates Unexposed to Maternal MgSO4 Administration and in Neonates Exposed for Fetal Neuroprotection or Maternal Eclampsia Prevention.

Objective - To compare neonatal magnesemia in the first fifteen days of neonatal life between three groups: a control group not exposed to MgSO4, a neuroprotection group, and an eclampsia prevention group, and to explore its’ associations with child outcomes. Design - Retrospective single-centre cohort study. Setting - Tertiary care setting. Population - Infants admitted at the neonatal intensive care unit born between 24 and 32 weeks’ gestation, regardless of etiology of preterm birth.Methods - Linear mixed regression of neonatal magnesemia on exposure group and day of life. Generalised estimating equations models of child outcomes on neonatal magnesemia according to exposure group and day of life. Main outcome measures - Neonatal magnesemia (mmol/l). Results - Neonatal magnesemia is significantly higher in the preeclampsia group compared to the control and neuroprotection group. On the day of birth, this is irrespective of maternal magnesemia (preeclampsia vs control group), and the maternal total dose or duration of MgSO4 administration (preeclampsia vs neuroprotection group). No differences were found in short-term composite outcome between the three groups. Conclusions - We found mean differences in neonatal magnesemia between children not exposed to MgSO4 antenatally, children exposed for fetal neuroprotection, and children exposed for maternal eclampsia prevention. A 4g loading and 1g/h maintenance dose, for fetal neuroprotection and eclampsia prevention, appears to be safe on the short term for the neonate.

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

Antenatal magnesium sulfate (MgSO4) treatment is widely used for fetal neuroprotection in women at risk of preterm delivery. However, some studies have recently suggested that in utero MgSO4 exposure is associated with an increased risk of necrotizing enterocolitis (NEC). This study aimed to investigate the association between antenatal MgSO4 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 MgSO4 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 MgSO4. 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 unexposed and exposed to antenatal MgSO4 (5.1% vs. 3.6%, p = 0.369). These results showed that antenatal MgSO4 treatment was not associated with risk of NEC in our study population.