Magnesium sulfate use for fetal neuroprotection

Magnesium sulfate and risk of hypoxic-ischemic encephalopathy in a high-risk cohort

BACKGROUND

Hypoxic-ischemic encephalopathy contributes to morbidity and mortality among neonates ≥36 weeks of gestation. Evidence of preventative antenatal treatment is limited. Magnesium sulfate has neuroprotective properties among preterm fetuses. Hypertensive disorders of pregnancy are a risk factor for hypoxic-ischemic encephalopathy, and magnesium sulfate is recommended for maternal seizure prophylaxis among patients with preeclampsia with severe features.

OBJECTIVE

(1) Determine trends in the incidence of hypertensive disorders of pregnancy, antenatal magnesium sulfate, and hypoxic-ischemic encephalopathy; (2) evaluate the association between hypertensive disorders of pregnancy and hypoxic-ischemic encephalopathy; and (3) evaluate if, among patients with hypertensive disorders of pregnancy, the odds of hypoxic-ischemic encephalopathy is mitigated by receipt of antenatal magnesium sulfate.

STUDY DESIGN

We analyzed a prospective cohort of live births ≥36 weeks of gestation between 2012 and 2018 within the California Perinatal Quality Care Collaborative registry, linked with the California Department of Health Care Access and Information files. We used Cochran-Armitage tests to assess trends in hypertensive disorders, encephalopathy diagnoses, and magnesium sulfate utilization and compared demographic factors between patients with or without hypertensive disorders of pregnancy or treatment with magnesium sulfate. Hierarchical logistic regression models were built to explore if hypertensive disorders of pregnancy were associated with any severity and moderate/severe hypoxic-ischemic encephalopathy. Separate hierarchical logistic regression models were built among those with hypertensive disorders of pregnancy to evaluate the association of magnesium sulfate with hypoxic-ischemic encephalopathy.

RESULTS

Among 44,314 unique infants, the diagnosis of hypoxic-ischemic encephalopathy, maternal hypertensive disorders of pregnancy, and the use of magnesium sulfate increased over time. Compared with patients with hypertensive disorders of pregnancy alone, patients with hypertensive disorders treated with magnesium sulfate represented a high-risk population. They were more likely to be publicly insured, born between 36 and 38 weeks of gestation, be small for gestational age, have lower Apgar scores, require a higher level of resuscitation at delivery, have prolonged rupture of membranes, experience preterm labor and fetal distress, and undergo operative delivery (all P<.002). Hypertensive disorders of pregnancy were associated with hypoxic-ischemic encephalopathy (adjusted odds ratio, 1.26 [95% confidence interval, 1.13-1.40]; P<.001) and specifically moderate/severe hypoxic-ischemic encephalopathy (adjusted odds ratio, 1.26 [95% confidence interval, 1.11-1.42]; P<.001). Among patients with hypertensive disorders of pregnancy, treatment with magnesium sulfate was associated with 29% reduction in the odds of neonatal hypoxic-ischemic encephalopathy (adjusted odds ratio, 0.71 [95% confidence interval, 0.52-0.97]; P=.03) and a 37% reduction in the odds of moderate/severe neonatal hypoxic-ischemic encephalopathy (adjusted odds ratio, 0.63 [95% confidence interval, 0.42-0.94]; P=.03).

CONCLUSION

Hypertensive disorders of pregnancy are associated with hypoxic-ischemic encephalopathy and, specifically, moderate/severe disease. Among people with hypertensive disorders, receipt of antenatal magnesium sulfate is associated with a significant reduction in the odds of hypoxic-ischemic encephalopathy and moderate/severe disease in a neonatal cohort admitted to neonatal intensive care unit at ≥36 weeks of gestation. The findings of this observational study cannot prove causality and are intended to generate hypotheses for future clinical trials on magnesium sulfate in term infants.

Magnesium Sulfate-Induced Anaphylaxis: A Case Report and Review of the Literature

Anaphylaxis due to magnesium sulfate is uncommon with very few reported cases. We report a case of a 28-year-old female who had low serum magnesium and was given magnesium sulfate. She developed pruritic urticarial rash, hypoxemia, and stridor. Anaphylaxis was diagnosed, and she received epinephrine, diphenhydramine, and oxygen therapy causing resolution. The study also discusses similar published cases and their presentation and treatment. We have briefly overviewed the clinical criteria for the diagnosis of anaphylaxis. The study also intends to make the clinician consider anaphylaxis while administering magnesium sulfate for any reason.

Early pregnancy biomarker discovery study for spontaneous preterm birth

(1) OBJECTIVE: discover new candidate biomarkers for spontaneous preterm birth in early pregnancy samples. When fully clinically validated, early pregnancy biomarkers for sPTB give the possibility to intervene or monitor high-risk pregnancies more intensively through, as example, pelvic exams, ultrasound or sonographic cervical length surveillance. (2) STUDY DESIGN: Early pregnancy serum samples of eight spontaneous extreme and very preterm birth cases (<32 weeks of gestational age) without any symptoms of preeclampsia and fetal growth restriction and eight uncomplicated pregnancies were analyzed by liquid chromatography mass spectrometry (LC-MS). Thirteen proteins, which were differentially expressed according to the LC-MS data, were subsequently selected for confirmation by enzyme-linked immunosorbent assay (ELISA). (3) RESULTS: Differential expression of four candidate biomarkers was confirmed by ELISA with decreased early pregnancy levels of gelsolin and fibulin-1 and increased levels of c-reactive protein and complement C5 in the preterm birth group. (4) CONCLUSIONS: The confirmed candidate biomarkers are all to some extent related to inflammatory pathways and/or the complement system. This supports the hypothesis that both play a role in extreme and very preterm birth without any symptoms of preeclampsia and fetal growth restriction. The predictive value of complement C5, c-reactive protein, fibulin-1 and gelsolin should, therefore, be validated in another cohort with early pregnancy samples.

β3 Receptor Signaling in Pregnant Human Myometrium Suggests a Role for β3 Agonists as Tocolytics

Preterm labor leading to preterm birth is the leading cause of infant morbidity and mortality. At the present time, nothing can reliably halt labor once it begins. The knowledge that agonists of the β2 adrenergic receptor relax airway smooth muscle and are effective in the treatment of asthma led to the notion that β2 mimetics would prevent preterm birth by relaxing uterine smooth muscle. The activation of cAMP-dependent protein kinase by β2 receptors is unable to provide meaningful tocolysis. The failure of β2 agonists such as ritodrine and terbutaline to prevent preterm birth suggests that the regulation of uterine smooth muscle is disparate from that of airway. Other smooth muscle quiescent-mediating molecules, such as nitric oxide, relax vascular smooth muscle in a cGMP-protein kinase G-dependent manner; however, nitric oxide activation of protein kinase G fails to explain the relaxation of the myometrium to nitric oxide. Moreover, nitric oxide-mediated relaxation is blunted in preterm labor, and thus, for this reason and because of the fall in maternal blood pressure, nitric oxide cannot be employed as a tocolytic. The β3 adrenergic receptor-mediated relaxation of the human myometrium is claimed to be cAMP-dependent protein kinase-dependent. This is scientifically displeasing given the failure of β2 agonists as tocolytics and suggests a non-canonical signaling role for β3AR in myometrium. The addition of the β3 agonist mirabegron to pregnant human myometrial strips in the tissue bath relaxes oxytocin-induced contractions. Mirabegron stimulates nitric oxide production in myometrial microvascular endothelial cells, and the relaxation of uterine tissue in vitro is partially blocked by the addition of the endothelial nitric oxide synthase blocker Nω-Nitro-L-arginine. Recent data suggest that both endothelial and smooth muscle cells respond to β3 stimulation and contribute to relaxation through disparate signaling pathways. The repurposing of approved medications such as mirabegron (Mybetriq™) tested in human myometrium as uterine tocolytics can advance the prevention of preterm birth.

All Care is Brain Care: Neuro-Focused Quality Improvement in the Neonatal Intensive Care Unit

Neonates requiring intensive care are in a critical period of brain development that coincides with the neonatal intensive care unit (NICU) hospitalization, placing these infants at high risk of brain injury and long-term neurodevelopmental impairment. Care in the NICU has the potential to be both harmful and protective to the developing brain. Neuro-focused quality improvement efforts address 3 main pillars of neuroprotective care: prevention of acquired injury, protection of normal maturation, and promotion of a positive environment. Despite challenges in measurement, many centers have shown success with consistent implementation of best and potentially better practices that may improve markers of brain health and neurodevelopment.

Study of the Magnesium Comenate Structure, Its Neuroprotective and Stress-Protective Activity

The crystal structure and the biological activity of a new coordination compound of magnesium ions with comenic acid, magnesium comenate, was characterized and studied. Quantitative and qualitative analysis of the compound was investigated in detail using elemental X-ray fluorescent analysis, thermal analysis, IR-Fourier spectrometry, UV spectroscopy, NMR spectroscopy, and X-ray diffraction analysis. Based on experimental analytical data, the empirical formula of magnesium comenate [Mg(HCom)₂(H₂O)₆]·2H₂O was established. This complex compound crystallizes with eight water molecules, six of which are the hydration shell of the Mg²⁺ cation, and two more molecules bind the [Mg(H₂O)₆]²⁺ aquacation with ionized ligand molecules by intermolecular hydrogen bonds. The packing of molecules in the crystal lattice is stabilized by a branched system of hydrogen bonds with the participation of solvate water molecules and oxygen atoms of various functional groups of ionized ligand molecules. With regard to the biological activity of magnesium comenate, a neuroprotective, stress-protective, and antioxidant effect was established in in vitro and in vivo models. In in vitro experiments, magnesium comenate protected cerebellar neurons from the toxic effects of glutamate and contributed to the preservation of neurite growth parameters under oxidative stress caused by hydrogen peroxide. In animal studies, magnesium comenate had a stress-protective and antioxidant effect in models of immobilization-cold stress. Oral administration of magnesium comenate at a dose of 2 mg/kg of animal body weight for 3 days before stress exposure and for 3 days during the stress period led to a decrease in oxidative damage and normalization of the antioxidant system of brain tissues against the background of induced stress. The obtained results indicate the advisability of further studies of magnesium comenate as a compound potentially applicable in medicine for the pharmacological correction of conditions associated with oxidative and excitotoxic damage to nerve cells.

Magnesium Sulfate Use in Pregnancy for Preeclampsia Prophylaxis and Fetal Neuroprotection: Regimens in High-Income and Low/Middle-Income Countries

Magnesium sulfate is one of the most commonly used medications in obstetrics, most notably for the prevention of eclamptic seizures and fetal neuroprotection of the extremely preterm neonate. Pharmacokinetic and pharmacodynamic studies have demonstrated a variety of IV and IM regimens are effective for these indications. Existing models and data can be used to tailor treatment regimens to increase coverage in poor resource areas, maximize efficacy and minimize toxicity for patients of different weights and renal function.

The Association between Evidence-Based Healthcare Practices and Outcomes among Preterm Births in China

INTRODUCTION

Very preterm infants are at high risk of early death or severe brain injury, with potential for impaired long-term neurodevelopmental function and physical health. There are evidence-based healthcare practices that can reduce the incidence.

MATERIALS AND METHODS

Infants born at 24-316 weeks gestational age and admitted within 24 h to NICUs participating in the Chinese Neonatal Network in 2019 were included. We examined the association between 4 evidence-based practices: inborn (born in a tertiary hospital in the Chinese Neonatal Network), ACS (any antenatal corticosteroid), MgSO4 (prenatal magnesium sulfate), and NT (normothermic temperature [36.0-37.5°C] at admission) and early death and/or severe brain injury in the study population.

RESULTS

Of 6,035 eligible infants, the incidence of early death and/or severe brain injury was 10.6%. Exposure to ACS only was associated with significant lower incidence of death and/or severe brain injury than none (aOR, 0.71; 95% CI: 0.57-0.88), but not MgSO4 only (aOR, 0.97; 95% CI: 0.81-1.17), NT only (aOR, 0.91; 95% CI: 0.76-1.08), or inborn only (aOR, 0.91; 95% CI: 0.72-1.15). The association between number of practices and incidence of early death and/or severe brain injury is as follows: none = 23% (31/138), any 1 = 14% (84/592), any 2 = 12% (185/1,538), any 3 = 9% (202/2,285), and all 4 = 9% (140/1,482).

DISCUSSION/CONCLUSION

More comprehensive use of evidence-based practices was associated with improved survival without severe brain injury among very preterm infants born at <32 weeks gestational age.