Antenatal magnesium sulfate is beneficial or harmful in very preterm and extremely preterm neonates: a new insight

Antenatal Magnesium Sulfate Is Not Associated With Improved Long-Term Neurodevelopment and Growth in Very Low Birth Weight Infants

BACKGROUND

Though antenatal magnesium sulfate (MgSO4) is widely used for fetal neuroprotection, suspicions about the long-term neuroprotection of antenatal MgSO4 have been raised.

METHODS

We investigated short- and long-term outcomes of antenatal MgSO4 use for 468 infants weighing < 1,500 g with a gestational age of 24-31 weeks.

RESULTS

Short-term morbidities and the risk of developmental delay, hearing loss, and cerebral palsy at a corrected age of 18-24 months and 3 years of age did not decrease in the MgSO4 group (infants who were exposed to MgSO4 for any purpose) or neuroprotection group (infants who were exposed to MgSO4 for fetal neuroprotection) compared with the control group (infants who were not exposed to MgSO4). The z-scores of weight, height, and head circumference did not increase in the MgSO4 group or neuroprotection group compared with the control group.

CONCLUSION

Antenatal MgSO4 including MgSO4 for neuroprotection did not have beneficial effects on long-term neurodevelopmental and growth outcomes.

Antenatal Neuroprotective Magnesium Sulfate in Very Preterm Infants and Its Association With Feeding Intolerance

INTRODUCTION/OBJECTIVE

Magnesium sulfate (MgSO 4 ) treatment is widely used for fetal neuroprotection despite the controversy concerning the side effects. There is limited data regarding the impact of various cumulative maternal doses and neonatal serum magnesium (Mg) levels on short-term neonatal morbidity and mortality. We opted to carry out a study to determine the impact of neonatal serum Mg levels on neonatal outcomes.

METHOD

We conducted this prospective observational study between 2017 and 2021. Antenatal MgSO 4 was used for neuroprotective purpose only during the study period. Inborn preterm infants delivered between 23 and 31 6/7 weeks of gestation were enrolled consecutively. Babies who underwent advanced resuscitation in the delivery room, inotropic treatment due to hemodynamic instability in the first 7 days of life, >12 hours since the discontinuation of maternal MgSO 4 treatment, severe anemia, and major congenital/chromosomal anomalies were excluded from the study. The subgroup of babies with serum Mg level at the 6th hour of life underwent an analysis. A neonatal Mg concentration of 2.5 mg/dL was used to classify MgSO 4 -exposed patients into 2 groups (<2.5 mg/dL and ≥2.5 mg/dL). Another analysis was performed between babies whose mothers were exposed to MgSO 4 and those not exposed. Finally, the groups' neonatal outcomes were compared.

RESULTS

Of the 584 babies, 310 received antenatal MgSO 4 . The birth weights were significantly lower in the MgSO 4 exposed group (1113 ± 361 g vs 1202 ± 388 g, P = 0.005). Antenatal corticosteroid usage and intrauterine growth restriction were also noted to be higher. The MgSO 4 group was more likely to have bronchopulmonary dysplasia, prolonged invasive ventilation, necrotizing enterocolitis, delayed enteral nutrition, and feeding intolerance ( P < 0.05). MgSO 4 treatment was shown as an independent risk factor for feeding intolerance when corrected for confounders (odds ratio 2.13, 95% confidence interval: 1.4-3.1, P = 0.001). Furthermore, serum Mg level significantly correlated with feeding intolerance ( r = 0.21, P = 0.002).

CONCLUSION

This study highlighted the effect of MgSO 4 treatment and the potential superiority of serum Mg level as a predictor of immediate neonatal outcomes, particularly delayed enteral nutrition and feeding intolerance. Further studies are warranted to ascertain the optimal serum Mg concentration of preterm infants in early life to provide maximum benefit with minimal side effects.

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

INTRODUCTION

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.

METHODS

The incidences of complicated MRI requiring aggressive enema or surgical intervention and other intestinal complications were compared among period 1 (January 2012-December 2013, n = 79), before adoption of the antenatal MgSO4 protocol for fetal neuroprotection; period 2 (January 2014-March 2016, n = 72), when the protocol was adopted; and period 3 (April 2016-September 2018, n = 75), when the protocol was temporarily withdrawn due to concern regarding intestinal complications in EPIs.

RESULTS

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%, p = 0.391, and 11% vs. 0% and 1%, p = 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).

CONCLUSION

Antenatal MgSO4 may increase the risk of MRI, frequently requiring surgical intervention, in EPIs with a gestational age of 25 weeks or less.

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 exposed and unexposed 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.

Antenatal magnesium sulphate and adverse neonatal outcomes: A systematic review and meta-analysis

BACKGROUND

There is widespread, increasing use of magnesium sulphate in obstetric practice for pre-eclampsia, eclampsia, and preterm fetal neuroprotection; benefit for preventing preterm labour and birth (tocolysis) is unproven. We conducted a systematic review and meta-analysis to assess whether antenatal magnesium sulphate is associated with unintended adverse neonatal outcomes.

METHODS AND FINDINGS

CINAHL, Cochrane Library, LILACS, MEDLINE, Embase, TOXLINE, and Web of Science, were searched (inceptions to 3 September 2019). Randomised, quasi-randomised, and non-randomised trials, cohort and case-control studies, and case reports assessing antenatal magnesium sulphate for pre-eclampsia, eclampsia, fetal neuroprotection, or tocolysis, compared with placebo/no treatment or a different magnesium sulphate regimen, were included. The primary outcome was perinatal death. Secondary outcomes included pre-specified and non-pre-specified adverse neonatal outcomes. Two reviewers screened 5,890 articles, extracted data, and assessed risk of bias following Cochrane Handbook and RTI Item Bank guidance. For randomised trials, pooled risk ratios (RRs) or mean differences, with 95% confidence intervals (CIs), were calculated using fixed- or random-effects meta-analysis. Non-randomised data were tabulated and narratively summarised. We included 197 studies (40 randomised trials, 138 non-randomised studies, and 19 case reports), of mixed quality. The 40 trials (randomising 19,265 women and their babies) were conducted from 1987 to 2018 across high- (16 trials) and low/middle-income countries (23 trials) (1 mixed). Indications included pre-eclampsia/eclampsia (24 trials), fetal neuroprotection (7 trials), and tocolysis (9 trials); 18 trials compared magnesium sulphate with placebo/no treatment, and 22 compared different regimens. For perinatal death, no clear difference in randomised trials was observed between magnesium sulphate and placebo/no treatment (RR 1.01; 95% CI 0.92 to 1.10; 8 trials, 13,654 babies), nor between regimens. Eleven of 138 non-randomised studies reported on perinatal death. Only 1 cohort (127 babies; moderate to high risk of bias) observed an increased risk of perinatal death with >48 versus ≤48 grams magnesium sulphate exposure for tocolysis. No clear secondary adverse neonatal outcomes were observed in randomised trials, and a very limited number of possible adverse outcomes warranting further consideration were identified in non-randomised studies. Where non-randomised studies observed possible harms, often no or few confounders were controlled for (moderate to high risk of bias), samples were small (200 babies or fewer), and/or results were from subgroup analyses. Limitations include missing data for important outcomes across most studies, heterogeneity of included studies, and inclusion of published data only.

CONCLUSIONS

Our findings do not support clear associations between antenatal magnesium sulphate for beneficial indications and adverse neonatal outcomes. Further large, high-quality studies (prospective cohorts or individual participant data meta-analyses) assessing specific outcomes, or the impact of regimen, pregnancy, or birth characteristics on these outcomes, would further inform safety recommendations. PROSPERO: CRD42013004451.