Protection of brain development by antenatal magnesium sulphate for infants born preterm

Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus

BACKGROUND

Magnesium sulphate is a common therapy in perinatal care. Its benefits when given to women at risk of preterm birth for fetal neuroprotection (prevention of cerebral palsy for children) were shown in a 2009 Cochrane review. Internationally, use of magnesium sulphate for preterm cerebral palsy prevention is now recommended practice. As new randomised controlled trials (RCTs) and longer-term follow-up of prior RCTs have since been conducted, this review updates the previously published version.

OBJECTIVES

To assess the effectiveness and safety of magnesium sulphate as a fetal neuroprotective agent when given to women considered to be at risk of preterm birth.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) on 17 March 2023, as well as reference lists of retrieved studies.

SELECTION CRITERIA

We included RCTs and cluster-RCTs of women at risk of preterm birth that assessed prenatal magnesium sulphate for fetal neuroprotection compared with placebo or no treatment. All methods of administration (intravenous, intramuscular, and oral) were eligible. We did not include studies where magnesium sulphate was used with the primary aim of preterm labour tocolysis, or the prevention and/or treatment of eclampsia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed RCTs for inclusion, extracted data, and assessed risk of bias and trustworthiness. Dichotomous data were presented as summary risk ratios (RR) with 95% confidence intervals (CI), and continuous data were presented as mean differences with 95% CI. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included six RCTs (5917 women and their 6759 fetuses alive at randomisation). All RCTs were conducted in high-income countries. The RCTs compared magnesium sulphate with placebo in women at risk of preterm birth at less than 34 weeks' gestation; however, treatment regimens and inclusion/exclusion criteria varied. Though the RCTs were at an overall low risk of bias, the certainty of evidence ranged from high to very low, due to concerns regarding study limitations, imprecision, and inconsistency. Primary outcomes for infants/children: Up to two years' corrected age, magnesium sulphate compared with placebo reduced cerebral palsy (RR 0.71, 95% CI 0.57 to 0.89; 6 RCTs, 6107 children; number needed to treat for additional beneficial outcome (NNTB) 60, 95% CI 41 to 158) and death or cerebral palsy (RR 0.87, 95% CI 0.77 to 0.98; 6 RCTs, 6481 children; NNTB 56, 95% CI 32 to 363) (both high-certainty evidence). Magnesium sulphate probably resulted in little to no difference in death (fetal, neonatal, or later) (RR 0.96, 95% CI 0.82 to 1.13; 6 RCTs, 6759 children); major neurodevelopmental disability (RR 1.09, 95% CI 0.83 to 1.44; 1 RCT, 987 children); or death or major neurodevelopmental disability (RR 0.95, 95% CI 0.85 to 1.07; 3 RCTs, 4279 children) (all moderate-certainty evidence). At early school age, magnesium sulphate may have resulted in little to no difference in death (fetal, neonatal, or later) (RR 0.82, 95% CI 0.66 to 1.02; 2 RCTs, 1758 children); cerebral palsy (RR 0.99, 95% CI 0.69 to 1.41; 2 RCTs, 1038 children); death or cerebral palsy (RR 0.90, 95% CI 0.67 to 1.20; 1 RCT, 503 children); and death or major neurodevelopmental disability (RR 0.81, 95% CI 0.59 to 1.12; 1 RCT, 503 children) (all low-certainty evidence). Magnesium sulphate may also have resulted in little to no difference in major neurodevelopmental disability, but the evidence is very uncertain (average RR 0.92, 95% CI 0.53 to 1.62; 2 RCTs, 940 children; very low-certainty evidence). Secondary outcomes for infants/children: Magnesium sulphate probably reduced severe intraventricular haemorrhage (grade 3 or 4) (RR 0.76, 95% CI 0.60 to 0.98; 5 RCTs, 5885 infants; NNTB 92, 95% CI 55 to 1102; moderate-certainty evidence) and may have resulted in little to no difference in chronic lung disease/bronchopulmonary dysplasia (average RR 0.92, 95% CI 0.77 to 1.10; 5 RCTs, 6689 infants; low-certainty evidence). Primary outcomes for women: Magnesium sulphate may have resulted in little or no difference in severe maternal outcomes potentially related to treatment (death, cardiac arrest, respiratory arrest) (RR 0.32, 95% CI 0.01 to 7.92; 4 RCTs, 5300 women; low-certainty evidence). However, magnesium sulphate probably increased maternal adverse effects severe enough to stop treatment (average RR 3.21, 95% CI 1.88 to 5.48; 3 RCTs, 4736 women; moderate-certainty evidence). Secondary outcomes for women: Magnesium sulphate probably resulted in little to no difference in caesarean section (RR 0.96, 95% CI 0.91 to 1.02; 5 RCTs, 5861 women) and postpartum haemorrhage (RR 0.94, 95% CI 0.80 to 1.09; 2 RCTs, 2495 women) (both moderate-certainty evidence). Breastfeeding at hospital discharge and women's views of treatment were not reported.

AUTHORS' CONCLUSIONS

The currently available evidence indicates that magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus, compared with placebo, reduces cerebral palsy, and death or cerebral palsy, in children up to two years' corrected age, and probably reduces severe intraventricular haemorrhage for infants. Magnesium sulphate may result in little to no difference in outcomes in children at school age. While magnesium sulphate may result in little to no difference in severe maternal outcomes (death, cardiac arrest, respiratory arrest), it probably increases maternal adverse effects severe enough to stop treatment. Further research is needed on the longer-term benefits and harms for children, into adolescence and adulthood. Additional studies to determine variation in effects by characteristics of women treated and magnesium sulphate regimens used, along with the generalisability of findings to low- and middle-income countries, should be considered.

Neuroprotective Effects of Artificial Cerebrospinal Fluid: Analysis of Brainstem Auditory-Evoked Potential Monitoring During Microvascular Decompression in 117 Consecutive Patients

BACKGROUND AND OBJECTIVES

To study the efficacy of irrigation with artificial cerebrospinal fluid (aCSF) for protection of cranial nerves during surgery; the time required for recovery of brainstem auditory-evoked potentials (BAEPs) that would reflect cochlear function was analyzed in comparison with that for saline irrigation.

METHODS

This retrospective study included 117 consecutive patients (95 women, mean age 51.5 ± 11.4 year) who underwent microvascular decompression for hemifacial spasm. During surgery, BAEPs were monitored to avoid damage to the auditory pathways. When a delayed latency of >1 ms or a decrease in amplitude of >50% was detected in BAEP wave V, surgical maneuvers were halted, and the operative field was irrigated with saline or aCSF. Saline was used for irrigation in 58 patients and aCSF in the other 59. The time required for BAEP recovery at the first halt in each patient was analyzed, and the results were compared between the groups.

RESULTS

Surgical procedures were interrupted because of BAEP latency delays or decreases in amplitude in 51 of the patients in the saline group and 54 in the aCSF group. In both groups, the latencies and amplitudes recovered significantly with time and both recovered earlier after aCSF irrigation than after saline irrigation. Hearing outcome was not significantly different between 2 groups.

CONCLUSION

aCSF is effective for protection of cochlear nerve and promotes recovery from transient dysfunction during surgery. The protective effect may be attributed to multiple factors including conditioned pH, electrolyte composition, glucose, and microelements, such as magnesium and phosphate.

Serum Magnesium Level as a Biomarker to Predict the Risk of Labor Epidural Anesthesia Associated Fever

Objective

Excessive pain will have adverse effects on the mother and fetus. Labor epidural analgesia greatly reduces the pain, which is widely carried out abroad. Labor epidural anesthesia-associated fever (LEAF) is the biggest problem for labor epidural anesthesia. This study aimed to evaluate the clinical value of serum magnesium levels to predict the LEAF.

Methods

Overall 528 singleton term-pregnant women who underwent labor epidural anesthesia in Fujian Provincial Maternity and Children's Health Hospital, affiliated hospital of Fujian Medical University from January 2019 to June 2019, were analyzed retrospectively. The serum magnesium level was detected using venous blood samples. The relationship between the serum magnesium level and LEAF was interpreted, and the optimal cut-off values of the serum magnesium level to predict LEAF were calculated.

Results

Overall, 65 (12.30%) participants had LEAF. And a higher rate of the bulging membrane, gestational hypertension, neonatal intensive care unit (NICU) admission, and the different mode of delivery was significantly associated with LEAF. Also, the serum magnesium level demonstrated higher significantly in presence of LEAF than absence (P<0.05). What is more, it indicated that the area under the receiver operating characteristic curve (AUC) for the serum magnesium level was 0.825, and an optimal cut-off of the serum magnesium level was 0.855 mg/dl. Furthermore, it demonstrated that the serum magnesium level had the highest OR (OR= 7.49; 95% CI (4.58-14.35)) (P<0.001). The bulging membrane is an independent risk factor presence of LEAF (OR = 1.55; 95% CI (1.01-2.43)) (P=0.038).

Conclusion

This study demonstrated that the baseline of serum magnesium can provide a suitable biomarker to predict LEAF. It can help to provide a useful target for LEAF treatment and enhance surveillance before fever.

Molecular Pathways of Altered Brain Development in Fetuses Exposed to Hypoxia

Perinatal hypoxia is a major cause of neurodevelopmental impairment and subsequent motor and cognitive dysfunctions; it is associated with fetal growth restriction and uteroplacental dysfunction during pregnancy. This review aims to present the current knowledge on brain development resulting from perinatal asphyxia, including the causes, symptoms, and means of predicting the degree of brain damage. Furthermore, this review discusses the specificity of brain development in the growth-restricted fetus and how it is replicated and studied in animal models. Finally, this review aims at identifying the least understood and missing molecular pathways of abnormal brain development, especially with respect to potential treatment intervention.

Modulatory effect of two regimens of magnesium sulfate on the systemic inflammatory response in pregnant women with imminent eclampsia

OBJECTIVE

This study compared the modulatory effect of two intravenous magnesium sulfate (MgSO₄) regimens on the systemic inflammatory response in pregnant women diagnosed with imminent eclampsia.

STUDY DESIGN

In a single-blind cross-sectional study, 33 women were allocated according to the Zuspan (n = 16) and Sibai (n = 17) MgSO₄ regimens, and treated for 24 h. Blood samples were collected pre-administration of the loading dose, at 24 h of the maintenance dose of MgSO₄, and at 48 h, when patients were without treatment. Plasma was used to determine interleukin (IL)-1 beta (IL-1β), IL-6, IL-10, tumor necrosis factor-alpha (TNF-α), heat shock protein (Hsp70), and heme oxygenase-1 (HO-1) by ELISA.

RESULTS

The treatment with the Zuspan's regimen didn't change plasma concentrations of TNF-α, IL-10, and Hsp70 in the three-time points studied. However, it decreased IL-1β at 24 h and 48 h and IL-6 at 48 h, and increased HO-1 concentration at 48 h. On the other hand, compared to the pre-treatment period, Sibai's regimen induced a significant decrease in TNF-α, IL-1β, IL-6, and Hsp70, while increased HO-1 levels both at 24 h and 48 h and, IL-10 concentration at 48 h.

CONCLUSIONS

Sibai's regimen determined an early and efficient immunoregulatory effect on systemic inflammatory response in preeclampsia, suggesting that the maintenance dose of two grams of MgSO₄ was better than one gram in the treatment of imminent eclampsia.

Cerebral Palsy in Very Preterm Infants: A Nine-Year Prospective Study in a French Population-Based Tertiary Center

OBJECTIVES

To describe the prevalence of cerebral palsy (CP) at age 2 years in infants born before 33 weeks of gestation and to analyze the fetal neuroprotective effect of the antenatal administration of magnesium sulfate (MgSO₄) treatment on CP.

STUDY DESIGN

Preterm infants born before 33 weeks of gestation and discharged from the Rouen University Hospital's Neonatal Intensive Care Unit between 2007 and 2015 were included. At age 2 years, pediatricians of the perinatal network of Eure and Seine-Maritime counties administered standardized questionnaires analyzing motor, cognitive, and behavioral items, derived from the Denver and Amiel-Tison scales. A routine protocol based on MgSO₄ infusion was introduced in 2010. The primary outcome measure was the occurrence of CP according to the Surveillance of Cerebral Palsy in Europe network definition.

RESULTS

A total of 1759 very preterm infants were included, among whom 138 (7.8%) died and 148 (9.1%) were lost to follow-up. Assuming that those lost to follow-up had no CP, at 2 years, 55 of 1621 infants (3.4%; 95% CI, 2.6%-4.4%) had CP. After statistical adjustment for birth term and antenatal corticosteroid use, a significant decrease in CP was observed after implementation of a protocol of MgSO₄ administration in mothers before imminent preterm birth at <33 weeks of gestation (aOR, 0.53; 95% CI, 0.29-0.98; P = .04).

CONCLUSIONS

The prevalence of CP at 2 years after very preterm birth was low. The implementation of a neuroprotective protocol with MgSO₄ was associated with reduced CP occurrence; however, several relevant limitations must be considered for interpretation.

Guidelines for the management of women with severe pre-eclampsia

OBJECTIVE

To provide national guidelines for the management of women with severe pre-eclampsia.

DESIGN

A consensus committee of 26 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised.

METHODS

The last SFAR and CNGOF guidelines on the management of women with severe pre-eclampsia were published in 2009. The literature is now sufficient for an update. The aim of this expert panel guidelines is to evaluate the impact of different aspects of the management of women with severe preeclampsia on maternal and neonatal morbidities separately. The experts studied questions within 7 domains. Each question was formulated according to the PICO (Patients Intervention Comparison Outcome) model and the evidence profiles were produced. An extensive literature review and recommendations were carried out and analysed according to the GRADE® methodology.

RESULTS

The SFAR/CNGOF experts panel provided 25 recommendations: 8 have a high level of evidence (GRADE 1+/-), 9 have a moderate level of evidence (GRADE 2+/-), and for 7 recommendations, the GRADE method could not be applied, resulting in expert opinions. No recommendation was provided for 3 questions. After one scoring round, strong agreement was reached between the experts for all the recommendations.

CONCLUSIONS

There was strong agreement among experts who made 25 recommendations to improve practices for the management of women with severe pre-eclampsia.

Effect of cerebrolysin on neurodevelopmental outcome of high risk preterm infants: A randomized controlled trial

BACKGROUND

A significant proportion of preterm infants experience developmental delay despite receiving a post discharge early interventional care. Cerebrolysin is a peptide mixture which acts similar to endogenous neurotrophic factors through promoting neurogenesis and enhancing neuronal plasticity.

OBJECTIVE

To compare the effect of Cerebrolysin plus routine intervention program versus routine intervention program alone on the outcome of preterm infants at high risk for neurodevelopmental delay.

METHODS

In a randomized controlled trial, high-risk preterm infants <  32 weeks' gestation who have abnormal neurological assessment at two months corrected post-natal age were randomized at 6 months corrected post natal age to receive either early intervention program or early intervention program plus Cerebrolysin injection of 0.1 mL/kg body weight every week for 3 months as an adjuvant therapy. The primary outcome was the rate of failure of the gross motor assessment at 12 months of corrected age and secondary outcomes included fine motor, language, and personal social development at 12 months corrected post-natal age as assessed by Denver Developmental Screening Test II.

RESULTS

Cerebrolysin group had a significant lower number of infants diagnosed with failed gross motor development compared to infants in the routine intervention group [10 (33%) versus 21 (70%), p = 0.009]. Cerebrolysin group had a significant lower number of infants diagnosed with failed fine motor, language and personal social development compared to infants in the routine intervention group.

CONCLUSION

Cerebrolysin, as an adjuvant therapy to routine early interventional care, may improve gross motor development of high-risk preterm infants at 12 months corrected post-natal age.

Effect of Neuroprotective Magnesium Sulfate Treatment on Brain Transcription Response to Hypoxia Ischemia in Neonate Mice

MgSO₄ is widely used in the prevention of preterm neurological disabilities but its modes of action remain poorly established. We used a co-hybridization approach using the transcriptome in 5-day old mice treated with a single dose of MgSO₄ (600 mg/kg), and/or exposed to hypoxia-ischemia (HI). The transcription of hundreds of genes was altered in all the groups. MgSO₄ mainly produced repressions culminating 6 h after injection. Bio-statistical analysis revealed the repression of synaptogenesis and axonal development. The putative targets of MgSO₄ were Mnk1 and Frm1. A behavioral study of adults did not detect lasting effects of neonatal MgSO₄ and precluded NMDA-receptor-mediated side effects. The effects of MgSO₄ plus HI exceeded the sum of the effects of separate treatments. MgSO₄ prior to HI reduced inflammation and the innate immune response probably as a result of cytokine inhibition (Ccl2, Ifng, interleukins). Conversely, MgSO₄ had little effect on HI-induced transcription by RNA-polymerase II. De novo MgSO₄-HI affected mitochondrial function through the repression of genes of oxidative phosphorylation and many NAD-dehydrogenases. It also likely reduced protein translation by the repression of many ribosomal proteins, essentially located in synapses. All these effects appeared under the putative regulatory MgSO₄ induction of the mTORC2 Rictor coding gene. Lasting effects through Sirt1 and Frm1 could account for this epigenetic footprint.

Advances in cerebral palsy biomarkers

Cerebral palsy (CP), defined as a group of nonprogressive disorders of movement and posture, is the most common cause of severe neurodisability in children. The prevalence of CP is the same across the globe, affecting approximately 17 million people worldwide. Cerebral Palsy is an umbrella term used to describe the disease due to its inherent heterogeneity. For instance, CP has multiple (1) causes; (2) clinical types; (3) patterns of neuropathology on brain imaging and (4) it's associated with several developmental pathologies such as intellectual disability, autism, epilepsy, and visual impairment. Understanding its physiopathology is crucial to developing protective strategies. Despite its importance, there is still insufficient progress in the areas of CP prediction, early diagnosis, treatment, and prevention. Herein we describe the current risk factors and biomarkers used for the diagnosis and prediction of CP. With the advancement in biomarker discovery, we predict that our understanding of the etiopathophysiology of CP will also increase, lending to more opportunities for developing novel treatments and prognosis.

Incidence and Risk Factors for Hypoglycemia During Fetal-to-Neonatal Transition in Premature Infants

Objective: To determine the incidence and risk factors associated with neonatal hypoglycemia in the premature population <33 weeks' gestation. Methods: This was a secondary retrospective analysis from previous infants enrolled in randomized controlled trials. A total of 255 infants <33 weeks' gestation were born during the study period. Eight infants were excluded due to missing glucose or maternal data and 175 infants were analyzed. Main outcome measures: Primary outcome was hypoglycemia (blood glucose <2.6mmol/L) determined via glucose oxidase method on arterial or venous blood gas. Birth weight subgroups: small for gestational age (SGA, birth weight <10%ile for gestational age) and large for gestational age (LGA, birth weight >90%ile for gestational age). Maternal hypertension was systolic blood pressure >140mmHg. Results: 175 infants <33 weeks' gestational age (89 male, 84 female) were analyzed. Hypoglycemia occurred in 59 infants (33.7%). Maternal hypertension (OR 3.07, 95% CI 1.51-6.30, p = 0.002) was the sole risk factor for neonatal hypoglycemia. Protective factors for hypoglycemia included labor at time of delivery (OR 4.51, 95% CI 2.29-9.18, p <0.0001) and antenatal magnesium sulfate (OR 2.53, 95% CI 1.23-5.50, p = 0.01). There were no significant differences between hypoglycemic and euglycemic infants in sex, gestational age, LGA infants, antenatal steroids, vaginal birth, or maternal diabetes. SGA infants were excluded from analysis due to sample size. Conclusions: Premature infants <33 weeks' gestation have increased risk of hypoglycemia. Maternal hypertension increases hypoglycemia risk. Antenatal magnesium sulfate administration or labor at time of delivery decrease hypoglycemia risk.

The development of neonatal neurointensive care

Brain injury remains one of the major unsolved problems in neonatal care, with survivors at high risk of lifelong neurodisability. It is unlikely that a single intervention can ameliorate neonatal brain injury, given the complex interaction between pathological processes, developmental trajectory, genetic susceptibility, and environmental influences. However, a coordinated, interdisciplinary approach to understand the root cause enables early detection, and diagnosis with enhanced clinical care offering the best chance of improving outcomes and facilitate new lines of neuroprotective treatments. Adult neurointensive care has existed as a speciality in its own right for over 20 years; however, it is only recently that large prospective studies have demonstrated the benefit of this model of care. The 'Neuro-intensive Care Nursery' model originated at the University of California San Francisco in 2008, and since then a growing number of units worldwide have adopted this approach. As well as providing consistent coordinated care for infants from a multidisciplinary team, it provides opportunities for specialist education and training in neonatal neurology, neuromonitoring, neuroimaging and nursing. This review outlines the origins of brain-oriented care of the neonate and the development of the Neuro-NICU (neonatal intensive care unit) and discusses some of the challenges and opportunities in expanding this model of care.

Metabolomic Profiling of Cerebral Palsy Brain Tissue Reveals Novel Central Biomarkers and Biochemical Pathways Associated with the Disease: A Pilot Study

Cerebral palsy (CP) is one of the most common causes of motor disability in childhood, with complex and heterogeneous etiopathophysiology and clinical presentation. Understanding the metabolic processes associated with the disease may aid in the discovery of preventive measures and therapy. Tissue samples (caudate nucleus) were obtained from post-mortem CP cases (n = 9) and age- and gender-matched control subjects (n = 11). We employed a targeted metabolomics approach using both ¹H NMR and direct injection liquid chromatography-tandem mass spectrometry (DI/LC-MS/MS). We accurately identified and quantified 55 metabolites using ¹H NMR and 186 using DI/LC-MS/MS. Among the 222 detected metabolites, 27 showed significant concentration changes between CP cases and controls. Glycerophospholipids and urea were the most commonly selected metabolites used to develop predictive models capable of discriminating between CP and controls. Metabolomics enrichment analysis identified folate, propanoate, and androgen/estrogen metabolism as the top three significantly perturbed pathways. We report for the first time the metabolomic profiling of post-mortem brain tissue from patients who died from cerebral palsy. These findings could help to further investigate the complex etiopathophysiology of CP while identifying predictive, central biomarkers of CP.