A Systematic Review of Magnesium Sulfate for Perinatal Neuroprotection: What Have We Learnt From the Past Decade?

There is an important unmet need to improve long term outcomes of encephalopathy for preterm and term infants. Meta-analyses of large controlled trials suggest that maternal treatment with magnesium sulfate (MgSO₄) is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth. However, to date, follow up to school age has found an apparent lack of long-term clinical benefit. Because of this inconsistency, it remains controversial whether MgSO₄ offers sustained neuroprotection. We systematically reviewed preclinical and clinical studies reported from January 1 2010, to January 31 2020 to evaluate the most recent advances and knowledge gaps relating to the efficacy of MgSO₄ for the treatment of perinatal brain injury. The outcomes of MgSO₄ in preterm and term-equivalent animal models of perinatal encephalopathy were highly inconsistent between studies. None of the perinatal rodent studies that suggested benefit directly controlled body or brain temperature. The majority of the studies did not control for sex, study long term histological and functional outcomes or use pragmatic treatment regimens and many did not report controlling for potential study bias. Finally, most of the recent preterm or term human studies that tested the potential of MgSO₄ for perinatal neuroprotection were relatively underpowered, but nevertheless, suggest that any improvements in neurodevelopment were at best modest or absent. On balance, these data suggest that further rigorous testing in translational preclinical models of perinatal encephalopathy is essential to ensure safety and best regimens for optimal preterm neuroprotection, and before further clinical trials of MgSO₄ for perinatal encephalopathy at term are undertaken.

Assessing Creatine Supplementation for Neuroprotection against Perinatal Hypoxic-Ischaemic Encephalopathy: A Systematic Review of Perinatal and Adult Pre-Clinical Studies

There is an important unmet need to develop interventions that improve outcomes of hypoxic-ischaemic encephalopathy (HIE). Creatine has emerged as a promising neuroprotective agent. Our objective was to systematically evaluate the preclinical animal studies that used creatine for perinatal neuroprotection, and to identify knowledge gaps that need to be addressed before creatine can be considered for pragmatic clinical trials for HIE.

METHODS

We reviewed preclinical studies up to 20 September 2021 using PubMed, EMBASE and OVID MEDLINE databases. The SYRCLE risk of bias assessment tool was utilized.

RESULTS

Seventeen studies were identified. Dietary creatine was the most common administration route. Cerebral creatine loading was age-dependent with near term/term-equivalent studies reporting higher increases in creatine/phosphocreatine compared to adolescent-adult equivalent studies. Most studies did not control for sex, study long-term histological and functional outcomes, or test creatine post-HI. None of the perinatal studies that suggested benefit directly controlled core body temperature (a known confounder) and many did not clearly state controlling for potential study bias.

CONCLUSION

Creatine is a promising neuroprotective intervention for HIE. However, this systematic review reveals key knowledge gaps and improvements to preclinical studies that must be addressed before creatine can be trailed for neuroprotection of the human fetus/neonate.

Brief hypoxia in late gestation sheep causes prolonged disruption of fetal electrographic, breathing behaviours and can result in early labour

KEY POINTS

Brief episodes of severe fetal hypoxia can arise in late gestation as a result of interruption of normal umbilical blood flow Systemic parameters and blood chemistry indicate complete recovery within 1-2 hours, although the long-term effects on fetal brain functions are unknown Fetal sheep were subjected to umbilical cord occlusion (UCO) for 10 min at 131 days of gestation, and then monitored intensively until onset of labour or delivery (<145 days of gestation) Normal patterns of fetal behaviour, including breathing movements, episodes of high and low voltage electorcortical activity, eye movements and postural (neck) muscle activity, were disrupted for 3-10 days after the UCO Preterm labour and delivery occurred in a significant number of the pregnancies after UCO compared to the control (sham-UCO) cohort.

ABSTRACT

Complications arising from antepartum events such as impaired umbilical blood flow can cause significant fetal hypoxia. These complications can be unpredictable, as well as difficult to detect, and thus we lack a detailed understanding of the (patho)physiological changes that occur between the antenatal in utero event and birth. In the present study, we assessed the consequences of brief (∼10 min) umbilical cord occlusion (UCO) in fetal sheep at ∼0.88 gestation on fetal plasma cortisol concentrations and fetal behaviour [electrocortical (EcoG), electo-oculargram (EOG), nuchal muscle electromyography (EMG) and breathing activities] in the days following UCO. UCO caused a rapid onset of fetal hypoxaemia, hypercapnia, and acidosis; however, by 6 h, all blood parameters and cardiovascular status were normalized and not different from the control (Sham-UCO) cohort. Subsequently, the incidence of fetal breathing movements decreased compared to the control group, and abnormal behavioural patterns developed over the days following UCO and leading up to the onset of labour, which included increased high voltage and sub-low voltage ECoG and EOG activities, as well as decreased nuchal EMG activity. Fetuses subjected to UCO went into labour 7.9 ± 3.6 days post-UCO (139.5 ± 3.2 days of gestation) compared to the control group fetuses at 13.6 ± 3.3 days post-sham UCO (144 ± 2.2 days of gestation; P < 0.05), despite comparable increases in fetal plasma cortisol and a similar body weight at birth. Thus, a single transient episode of complete UCO late in gestation in fetal sheep can result in prolonged effects on fetal brain activity and premature labour, suggesting persisting effects on fetal cerebral metabolism.

Perinatal encephalopathy, the syndrome of intracranial hypertension and associated diagnostic labels in the Commonwealth of Independent States: a systematic review

BACKGROUND

The WHO reports excessive rates of ill-defined neurological diagnoses and ineffective and potentially harmful drug treatments in children in the Commonwealth of Independent States (CIS). Collectively termed perinatal encephalopathy and the syndrome of intracranial hypertension (PE-SIH), these diagnoses are important contributors to perceived childhood morbidity and disability in the CIS. A systematic compilation of information on PE-SIH is lacking.

METHODS

We systematically reviewed publications between 1970 and 2020 on PE-SIH in Azerbaijani, English, Russian and Ukrainian languages and summarised information on PE-SIH.

RESULTS

We identified 30 publications (70% in Russian) published 1976-2017. The diagnosis of PE-SIH was either based on unreported criteria (67% of reports), non-specific clinical features of typically developing children or those with common developmental disorders (20% of reports) or cranial ultrasound (13% of reports). The reported proportion of children with PE-SIH in the study samples ranged from 31% to 99%. There were few published studies on reassessments of children diagnosed with PE-SIH, and these did not confirm neurological disease in the majority of children. Treatments included multiple unlicenced drugs without established effectiveness and with potential unwanted effects.

CONCLUSION

This review suggests that PE-SIH is a medical diagnostic label that is used in numerous children without substantive associated disease. The diagnosis and treatment of PE-SIH is a multidimensional, iatrogenic, clinical and public health problem in the CIS. With increasing use of evidence-based medicine guidelines in the region, it is hoped that PE-SIH will gradually disappear, but actions to accelerate this change are nevertheless needed.

Association of Maternal Obesity and Neonatal Hypoxic-Ischemic Encephalopathy

Objective

More women are obese at their first prenatal visit and then subsequently gain further weight throughout pregnancy than ever before. The impact on the infant's development of neonatal hypoxic ischemic encephalopathy (HIE) has not been well studied. Using defined physiologic and neurologic criteria, our primary aim was to determine if maternal obesity conferred an additional risk of HIE.

Study Design

Data from the New York State Perinatal Data System of all singleton, term births in the Northeastern New York region were reviewed using the NIH obesity definition (Body Mass Index (BMI) ≥ 30 kg/m2). Neurologic and physiologic parameters were used to make the diagnosis of HIE. Physiologic criteria included the presence of an acute perinatal event, 10-min Apgar score ≤ 5, and metabolic acidosis. Neurologic factors included hypotonia, abnormal reflexes, absent or weak suck, hyperalert, or irritable state or evidence of clinical seizures. Therapeutic hypothermia was initiated if the infant met HIE criteria when assessed by the medical team. Logistic regression analysis was used to assess the effect of maternal body mass index on the diagnosis of HIE.

Results

In this large retrospective cohort study we evaluated outcomes of 97,488 pregnancies. Infants born to obese mothers were more likely to require ventilatory assistance and have a lower 5-min Apgar score. After adjusting for type of delivery and maternal risk factors, infants of obese mothers were diagnosed with HIE more frequently than infants of non-obese mothers, OR 1.96 (1.33-2.89) (p = 0.001).

Conclusion

Infants of obese mothers were significantly more likely to have the diagnosis of HIE.