Effects of Maternal Magnesium Sulfate Treatment on Neonatal Feeding Tolerance

Hypermagnesemia and feeding intolerance in preterm infants: a cohort study

BACKGROUND

Feeding intolerance (FI) is a common clinical problem in preterm infants often caused by some neonatal disorders and drugs, including antenatal exposure to magnesium sulfate (MgSO₄ ).

OBJECTIVE

To evaluate the association between hypermagnesemia at birth and FI in preterm infants during the first 72 hours of life.

METHOD

This was a cohort study conducted with preterm infants < 34 weeks of gestation. Infants presenting at least two of the following signs were considered as having FI: vomiting, abdominal distension, the need for continuous intermittent feeding, and delayed meconium passage. Hypermagnesemia was characterized by umbilical serum magnesium levels >2.5 mEq/l.

RESULTS

251 infants were evaluated. The median birth weight and gestational age were 1390 (IQR 1020 -1070) g and 31 (IQR 28-32) weeks, respectively. The FI rate was 17.5%. The exposure rate to MgSO₄ was similar in the tolerant and intolerant groups (53.1% x 63.6%, p=0.204), but hypermagnesemia was more frequent in the FI group (40.9% x 24.2%, p= 0.024). The univariate analysis showed that infants with hypermagnesemia were two-fold more likely to present FI (OR 2.16 95% CI 1.09-4.26). In the multiple logistic regression analysis, we found that hypermagnesemia was independently associated with FI (OR 2.51 - 95% CI 1.06-5.91), as well as maternal diabetes mellitus (OR 2.56 95% CI 1.07 - 6.14), SNAPPE-II (OR 1.051 95% CI 1.025-1.078), and brain hemorrhage (OR 3.61 95% CI 1.31 - 9.91).

CONCLUSION

In addition to other factors, hypermagnesemia at birth was independently associated with early feeding intolerance in preterm infants. This article is protected by copyright. All rights reserved.

Effects of maternal magnesium sulfate treatment on newborns

BACKGROUND

Antenatal magnesium sulfate (MgSO₄ ) has been used with mothers, but the influence of MgSO₄ on the fetus is unclear. The purpose of this study is to determine whether longer antenatal MgSO₄ exposure correlates with adverse effects in newborns.

METHODS

The clinical data of 77 infants born to mothers treated with MgSO₄ were collected. The infants were divided into two groups according to (1) the serum Mg concentration, (2) cumulative Mg dose, and (3) duration of antenatal maternal Mg treatment, respectively.

RESULTS

The serum Mg level of the infants correlated with that of the mothers but not with the duration of Mg treatment or the cumulative dose of Mg. There were no significant differences in the infants' clinical variables according to either the duration of Mg treatment or the cumulative dose of Mg. By contrast, enteral feeding tolerance began at a significantly later age and the heart rate on admission was significantly lower in infants with a serum Mg level ≥4.0 mmol/L than in those with a serum Mg level <4.0 mmol/L.

CONCLUSIONS

Modest effects on the clinical variables of infants with higher serum Mg levels were determined, whereas neither the duration of Mg treatment nor the cumulative Mg dose correlated with the clinical variables of the infants. Thus, in newborns with only moderately elevated serum Mg levels, serious adverse effects are unlikely.

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.

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

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.